What actual gains would you see from upgrading the exhaust manifolds on my 96 WRX wagon. Fitting a td05, decat and exhaust too.
I know remap is needed for max gains, would the reflash from polar or major_sarcasm be enough?

Cheers guys

 

So your upgrading to Jap import spec??

Then Turbo/Injectors and a Z4 Jap Import Ecu, and thats all you need.

 

It's an import anyway but only has td04 and 3B ecu....
Wanna get it up to around 300bhp, but by doing it safely too.
Will manifolds not do much then?
What injectors will it need?
And will fuel pump need upgrading too?

 

your injectors will be the same.

 

A manifold just isn't required at that level and you'll certainly not gain anything from the cheap ebay specials.
Changing the pump is never a bad idea baring in mind it's now 16 years old, so pop a Walbro in there for piece of mind.
If you are going to get it remapped, then a set of 440 (Yellows) from a 97/98 will be a straight fit and will give you the headroom required for your 300bhp.