ok, i should probably know the answer to this question but .....
i just recently installed cat-back exhaust, headers, crank pulley and accessory pulleys, and a CAI, do i need to upgrade my gas? if so, unleaded plus, or super unleaded premium?
thanks

 

if you still have ur stock engine, put in 87, u'll be wasting your $$ if you put anything higher

 

No. You're gonna get 10whp out of those mods and are not going FI (turbo, SC, or nitrous) so upgrading octane is not necessary.