1) From best motoring, the 8MR and IX have different turbo designs in terms of the intake.
2) From http://homepage2.nifty.com/lancer/turbo.htm,
a) the Evo 8MR turbos are 16G whilst the IX MR run 15G.
yes, the evo 8MR do have the same serial as per the EVO IX GSR (not the MR) where both are 16Gs.