i have a 2011 denali with the 3.42 gears and raced an silvy ss with LT headers and a intake. i was beating him by about two links and still pulling on him when i let up. i just have a tune intake and flowmaster dumps. just make sure u get a tune gm really chokes the 6.2's up with the engine abuse management and a tune really wakes them up, i also get much better gas mileage with the tune (around 16 in city) when i stay off it