diff --git a/retesteth/session/ToolBackend/ToolChain.cpp b/retesteth/session/ToolBackend/ToolChain.cpp
index c2249f58d..cd6d42a86 100644
--- a/retesteth/session/ToolBackend/ToolChain.cpp
+++ b/retesteth/session/ToolBackend/ToolChain.cpp
@@ -183,7 +183,8 @@ ToolResponse ToolChain::mineBlockOnTool(EthereumBlockState const& _block, SealEn
         if (tr.getCContent().gasLimit().asU256() <= c_maxGasLimit)  // tool fails on limits here.
             txs.addArrayObject(tr.getCContent().asDataObject(ExportOrder::ToolStyle));
         else
-            ETH_WARNING("Retesteth rejecting tx with gasLimit > 64 bits for tool");
+            ETH_WARNING(
+                "Retesteth rejecting tx with gasLimit > 64 bits for tool" + TestOutputHelper::get().testInfo().errorDebug());
     }
     writeFile(txsPath.string(), txs.asJson());
 
diff --git a/retesteth/testStructures/types/Ethereum/Transaction.cpp b/retesteth/testStructures/types/Ethereum/Transaction.cpp
index 4a435f46e..268a3a39a 100644
--- a/retesteth/testStructures/types/Ethereum/Transaction.cpp
+++ b/retesteth/testStructures/types/Ethereum/Transaction.cpp
@@ -49,6 +49,7 @@ void Transaction::fromDataObject(DataObject const& _data)
                 throw test::UpwardsException("Incorrect transaction `v` value: " + m_v.getCContent().asString());
             m_r = spVALUE(new VALUE(_data.atKey("r")));
             m_s = spVALUE(new VALUE(_data.atKey("s")));
+            rebuildRLP();
         }
         requireJsonFields(_data, "Transaction " + _data.getKey(),
             {
@@ -109,7 +110,6 @@ Transaction::Transaction(BYTES const& _rlp)
     fromRLP(rlp);
 }
 
-
 void Transaction::streamHeader(dev::RLPStream& _s) const
 {
     _s << nonce().asU256();
@@ -141,32 +141,21 @@ void Transaction::buildVRS(VALUE const& _secret)
     assignV(spVALUE(new VALUE(v)));
     assignR(spVALUE(new VALUE(r)));
     assignS(spVALUE(new VALUE(s)));
+    rebuildRLP();
 }
 
 void Transaction::assignV(spVALUE const _v) { m_v = _v; }
 void Transaction::assignR(spVALUE const _r) { m_r = _r; }
 void Transaction::assignS(spVALUE const _s) { m_s = _s; }
 
-BYTES const Transaction::getSignedRLP() const
+BYTES const& Transaction::getSignedRLP() const
 {
-    dev::RLPStream sWithSignature;
-    sWithSignature.appendList(9);
-    streamHeader(sWithSignature);
-    sWithSignature << v().asU256().convert_to<dev::byte>();
-    sWithSignature << r().asU256();
-    sWithSignature << s().asU256();
-    return BYTES(dev::toHexPrefixed(sWithSignature.out()));
+    return m_signedRLPdata.getCContent();
 }
 
-dev::RLPStream const Transaction::asRLPStream() const
+dev::RLPStream const& Transaction::asRLPStream() const
 {
-    dev::RLPStream out;
-    out.appendList(9);
-    streamHeader(out);
-    out << v().asU256().convert_to<dev::byte>();
-    out << r().asU256();
-    out << s().asU256();
-    return out;
+    return m_outRlpStream;
 }
 
 const DataObject Transaction::asDataObject(ExportOrder _order) const
@@ -202,9 +191,22 @@ const DataObject Transaction::asDataObject(ExportOrder _order) const
     return out;
 }
 
-FH32 Transaction::hash() const
+FH32 const& Transaction::hash() const
 {
-    return FH32("0x" + dev::toString(dev::sha3(asRLPStream().out())));
+    return m_hash.getCContent();
+}
+
+void Transaction::rebuildRLP()
+{
+    dev::RLPStream out;
+    out.appendList(9);
+    streamHeader(out);
+    out << v().asU256().convert_to<dev::byte>();
+    out << r().asU256();
+    out << s().asU256();
+    m_outRlpStream = out;
+    m_signedRLPdata = spBYTES(new BYTES(dev::toHexPrefixed(out.out())));
+    m_hash = spFH32(new FH32("0x" + dev::toString(dev::sha3(out.out()))));
 }
 
 }  // namespace teststruct
diff --git a/retesteth/testStructures/types/Ethereum/Transaction.h b/retesteth/testStructures/types/Ethereum/Transaction.h
index 5e3dc1327..5981c6efe 100644
--- a/retesteth/testStructures/types/Ethereum/Transaction.h
+++ b/retesteth/testStructures/types/Ethereum/Transaction.h
@@ -36,11 +36,11 @@ struct Transaction : GCP_SPointerBase
     VALUE const& v() const { return m_v.getCContent(); }
     VALUE const& r() const { return m_r.getCContent(); }
     VALUE const& s() const { return m_s.getCContent(); }
-    virtual FH32 hash() const;
+    FH32 const& hash() const;
     virtual TransactionType type() const { return TransactionType::LEGACY; }
 
-    virtual BYTES const getSignedRLP() const;
-    virtual dev::RLPStream const asRLPStream() const;
+    BYTES const& getSignedRLP() const;
+    dev::RLPStream const& asRLPStream() const;
     virtual DataObject const asDataObject(ExportOrder _order = ExportOrder::Default) const;
 
     virtual ~Transaction(){};
@@ -76,6 +76,12 @@ struct Transaction : GCP_SPointerBase
     void assignV(spVALUE const);
     void assignR(spVALUE const);
     void assignS(spVALUE const);
+
+    // Optimization
+    spFH32 m_hash;
+    dev::RLPStream m_outRlpStream;
+    spBYTES m_signedRLPdata;
+    virtual void rebuildRLP();
 };
 
 typedef GCP_SPointer<Transaction> spTransaction;
diff --git a/retesteth/testStructures/types/Ethereum/TransactionAccessList.cpp b/retesteth/testStructures/types/Ethereum/TransactionAccessList.cpp
index c78aa8cdb..5ac2381a6 100644
--- a/retesteth/testStructures/types/Ethereum/TransactionAccessList.cpp
+++ b/retesteth/testStructures/types/Ethereum/TransactionAccessList.cpp
@@ -18,6 +18,8 @@ TransactionAccessList::TransactionAccessList(DataObject const& _data, string con
     m_accessList = spAccessList(new AccessList(_data.atKey("accessList")));
     if (_data.count("secretKey"))
         buildVRS(VALUE(_data.atKey("secretKey")));  // Build without v + 27
+    else
+        rebuildRLP();
 }
 
 TransactionAccessList::TransactionAccessList(dev::RLP const& _rlp)
@@ -82,6 +84,7 @@ void TransactionAccessList::buildVRS(VALUE const& _secret)
     assignV(spVALUE(new VALUE(v)));
     assignR(spVALUE(new VALUE(r)));
     assignS(spVALUE(new VALUE(s)));
+    rebuildRLP();
 }
 
 void TransactionAccessList::streamHeader(dev::RLPStream& _s) const
@@ -106,31 +109,6 @@ void TransactionAccessList::streamHeader(dev::RLPStream& _s) const
     _s.appendRaw(accessList.out());
 }
 
-BYTES const TransactionAccessList::getSignedRLP() const
-{
-    return BYTES("0x" + dev::toHex(asRLPStream().out()));
-}
-
-dev::RLPStream const TransactionAccessList::asRLPStream() const
-{
-    // RLP(01 + tr.rlp)
-    dev::RLPStream wrapper;
-    dev::RLPStream out;
-    out.appendList(11);
-    streamHeader(out);
-    out << v().asU256().convert_to<dev::byte>();
-    out << r().asU256();
-    out << s().asU256();
-
-    // Alter output with prefixed 01 byte + tr.rlp
-    dev::bytes outa = out.out();
-    outa.insert(outa.begin(), dev::byte(1));
-
-    // Encode bytearray into rlp
-    wrapper << outa;
-    return wrapper;
-}
-
 DataObject const TransactionAccessList::asDataObject(ExportOrder _order) const
 {
     DataObject out = Transaction::asDataObject(_order);
@@ -146,9 +124,10 @@ DataObject const TransactionAccessList::asDataObject(ExportOrder _order) const
     return out;
 }
 
-FH32 TransactionAccessList::hash() const
+void TransactionAccessList::rebuildRLP()
 {
-    // HASH (01 + tr.rlp)
+    // RLP(01 + tr.rlp)
+    dev::RLPStream wrapper;
     dev::RLPStream out;
     out.appendList(11);
     streamHeader(out);
@@ -156,9 +135,15 @@ FH32 TransactionAccessList::hash() const
     out << r().asU256();
     out << s().asU256();
 
-    dev::bytes trRLP = out.out();
-    trRLP.insert(trRLP.begin(), dev::byte(1));
-    return FH32("0x" + dev::toString(dev::sha3(trRLP)));
+    // Alter output with prefixed 01 byte + tr.rlp
+    dev::bytes outa = out.out();
+    outa.insert(outa.begin(), dev::byte(1));
+
+    // Encode bytearray into rlp
+    wrapper << outa;
+    m_outRlpStream = wrapper;
+    m_signedRLPdata = spBYTES(new BYTES(dev::toHexPrefixed(m_outRlpStream.out())));
+    m_hash = spFH32(new FH32("0x" + dev::toString(dev::sha3(outa))));
 }
 
 
diff --git a/retesteth/testStructures/types/Ethereum/TransactionAccessList.h b/retesteth/testStructures/types/Ethereum/TransactionAccessList.h
index 7611d9992..82320a1bc 100644
--- a/retesteth/testStructures/types/Ethereum/TransactionAccessList.h
+++ b/retesteth/testStructures/types/Ethereum/TransactionAccessList.h
@@ -13,19 +13,16 @@ struct TransactionAccessList : Transaction
     TransactionAccessList(BYTES const&);
     TransactionAccessList(dev::RLP const&);
 
-    BYTES const getSignedRLP() const override;
-    dev::RLPStream const asRLPStream() const override;
     DataObject const asDataObject(ExportOrder _order = ExportOrder::Default) const override;
-
-    FH32 hash() const override;
     TransactionType type() const override { return TransactionType::ACCESSLIST; }
 
 private:
-    // void fromDataObject(DataObject const&) override;
     void fromRLP(dev::RLP const&) override;
 
     void buildVRS(VALUE const& _secret) override;
     void streamHeader(dev::RLPStream& _stream) const override;
+
+    void rebuildRLP() override;
     spAccessList m_accessList;
 };