If a Borla exhaust was tested to gain 10 HP at the wheels on a stock LT1 pumping out 230 HP, would you gain more if you were pumping out 300 + HP (say, 15 HP) or pretty much about the same? Thanks.

 

probobly a bit more, because you can use it all that much more

maybe +-2 hp... its when your start modding the motor that bolt ons really own

 

its true
all bolt ons do is make your engine run more efficiantly
thats it, no more
so if you let your engine exhaust gas faster, if it takes in air faster it will be even that much more going out

and also true when you use a cam it will need those headers, cat back to get rid of everything. and the cai to get it in better, so when you get the bolt ons and do the fun (fun being a loose term) mods the bolt ons thrive