anybody know what the differences are that make a standard my99/00 wrx import engine 280bhp compared to the uk engines lower bhp on same year? reason im asking is my bottom end is knocking on my version 6 wrx (not sti) so im looking for complete replacement engine as its probably easier/cheaper than rebuilding it but most i have come across for sale are out of uk turbo,s obviously dont want to lose the extra bhp my original import engine has by fitting a uk one. any help greatly appreciated sorry for the essay

 

Pretty sure the heads are slightly different, cam profiles i'd imagine. Everything else is down to the ancillaries, turbo ecu etc so if you get a short engine that'll be fine and you'd run the same power.
It's worth rebuilding though if you can afford it rather than use a second hand engine. You could run into the same problem in the not too distant future

 

thanks for the reply fella was thinking about getting an sti bottom end as obviously they are forged and using my heads etc as they are all fine would that be a good avenue to persue?

 

The pistons in the STI bottom end are forged but the rods and bearings are the usual chocolate ones so the engine is no stronger than a WRX version.

Its the ancilleries that give the import extra grunt over the UK versions. STI's run more aggressive cams and larger turbos and are mapped for higher octane fuel.