Most 10.2.0.4 SQL code will run faster on 11gR2 - this can only be validated by thorough testing.
Pl see these MOS Docs
Query Performance Degradation - Upgrade Related - Recommended Actions [ID 745216.1]
Using SQL Performance Analyzer to Test SQL Performance Impact of an Upgrade [ID 562899.1]
Things to Consider Before Upgrading to 22.214.171.124 to Avoid Poor Performance or Wrong Results [ID 1392633.1]