I did the SLP loudmouth, SLP long tubes, SLP underdrive pulley, and a LS6 cam...... no tune 345 hp to the wheels..... and the plus side is we stock everything here at the dealership!!!ouijaguy said:My thoughts all day long ponder the question of which exhaust i should go with. Performance is my main concern, second is sound. Any suggestions!? Also, do you need to reprogram the computer to work with a cat-back exhaust and an intake?