Just a quicky, on modern bikes you can download ECU maps off the net, use a laptop and cheap adaptor and remap it yourself based on the mods you have made..

why is this not possible on late Impreza's(MY00)which I understand have flashable ECUS?

 

Because if it was that easy nobody would pay the outragous 600 odd quid to these mapping companies to remap the ECU would they!!!

 

where can yo download these bike remaps?

 

The hardware adaptor is cheap. The software ain't!

There was talk about an open source version of this functionality; dunno what happened to that.