Will I receive any increase in power in my Classic STI 555 if I upgrade the headers/up pipe/downpipe & 3" straight through rear section without having it remapped?

 

Possibly but your asking to f@!k your car up, get it mapped if your going to do it, the differences will be very noticeable!

 

^^^^^
Exactly right.

 

Trouble is "as I understand it" (& I probably am wrong) I can't get my car mapped as it's running on it's original ECU??? (It's a 1995)

 

It's possible you can now..................

http://enduringsolutions.com/

 

you can do it and will notice a big difference, it will probably run a bit rich and may overboost, if it does you will need a boost controller,or fitting a z4 ecu works on a 93wrx as i have done it and done 80.000miles like it, but make sure you get your afr's checked to be safe
;

 

Would a Z4 increase performance from mine? Not sure what ECU mine runs but know they were 275 from factory.
I was looking to run 350 with Exhaust system (which I already have from an old car)/Better Intercooler/ TD 05 Turbo/ yellow injectors & uprated fuel pump. If I then have to figure into the price a new ECU(£?) & remap £300-400 it makes it seem like a huge amount of cash for a relatively small gain (max 75 BHP).

 

Im looking to get my car upgraded (its a standard 2001 WRX) and from what I can gather from weeks of reading forums from all over the shop is that a remap isnt just about numbers, it's about better spooling and response through the rev range. Yes, adding the various parts might make some gains, but power is nothing without control.

 

Spot on dude.

I just went all out with mine at the weekend, 2002 bug wrx.

A whole ruck of mods, finished with a super rom remap, launch control, duel map, anti lag etc etc.

Thee BEST money I've ever spent!! I'd reccomend a remap to anyone!!!

 

Without a remap you're asking for trouble. Simple as