Does installing the 727 mod cause problems with the tansmission on a '03 Raptor. Is there anything else you would have to do to the bike if I did the 727?

Is this the best one to get?

 

The trinity is a good choice, the only thing wrong with trinity is how slow they are and how they tell you your motor will be done at a certain time and it usually isn't. But the only things you would have to worry about would be the tranny the '03 tranny is stronger, but since you have to get the cases split and honed for the 727 piston you should prolly just get some sam coe gears that are even stronger just in case, also look at the sparks kits, they have won the 4-stroke races at glamis a few years in a row beatin 727 trinity's with there 690.