hi, first thank you for looking. but i got some questions

i have weapon r dragon short ram intake, weapon r egnine damper, megan 4-1 header and trd axle back muffler.

what is the less $$ i can spent but get maximum gains with the exhaust?

 

lightweight crank pulley

 

i meant what part i can modify with the exhaust.

 

2.25" piping from the cat to the canister.