2005 wrx
2006/2007 wrx
if you are only doing mild mods, the my06 would be much better! It has more displacement which means more torque for day to day driving. If you're not getting an STi, the benifits of the smaller engine won't be there. Forged pistons and rods only come in the STi. The wrx has the weaker rods and pistons that are about equal to that in the 06.