I have a twin dump decat down pipe (3inch) running into a wrx decat mid section (resonator only - 2.5inch I think) then into a scoobysport back box.

Wondering whether I will get any 'justifiable' extra bhp and torque if I change the mid section and back box all to 3inch - if so what is the best system per ££ or anyone got a mid section and back box for sale/swop +cash?

Cheers for any advice

 

I've been told that unless you're running 300horses + then no meaningful gain

Is that sound advice?

I've got around 265 horses ... (take some feeding I can tell you and as for the the mess! Great roses though and carrots to die for)