personally i wouldnt get it. it just makes the bike think its it 6th gear(baically an unrestricted gear) all the time so there is none of the slight jerking when you let off and give it gas(04-05models). my 06 didnt have any problem. there are no HP gains for the ZX10R with the TRE, It mearly helps drivability on the 04 and 05 models.Also dont get confused with it being called a TRE. It is marketed as a timing retarding device, but there is no timing retarding going on. It simply has the effect of making the secondary butterflies open up sooner. If you take out the secondary butterflies you get the same results. Also you need a map either way you go.