I have a 2002 400 sx, I decided to find some aftermarket parts, primarily a pipe and some other things to try and get a little more power. I have come to a conclusion that there is some stuff out there but not a wide selection too chose from, at least for a 2002 400sx so MY question is this: are the engine blocks and inner workings the same on 2003 and newer, if so would it be a good idea to change the piston and connecting rod and etc? so that I could just look for 2003 parts? I have thought about a big bore kit but that still leaves me with this question, after the big bore kit, they don't have any pipes for a 2002 450sx? would i just run a newer 450 pipe and would the frame bolts line up? please any tips or advice company names etc. thanks!!