Is it true with all the usuall bolt on mods we're probably paying about $100 per 1hp gain excluding NoS(ultimate bang for the buck) Add the total cost you have put into your ride and compare the hp gains, either advertise gains or roller gains. What's your avg?

I am making about 300HP at the flywheel and I have spent $4450 on performance parts. I installed the stuff my self so that helps a lot! I have paid about $40.45 per HP. Not bad I guess.

Hmmm Y-pipe = $300-$400
I know a y-pipe gains more than 3 or 4 HP.

CAI or Stillen or JWT = $100-$200+
They have more than 1 or 2 HP gains.

Catback Exhaust = $350-$500
Maybe this is where you question is true.