i don't want to bore it out because nothign is wrong with it an i wanan keep it 400 cc legal....
Outdoors you will be racing 450's as well, so unless you plan on running your 400ex in the stock class for the nationals (still against 450's) you can bore it out and not break any rules. For whatever class you run, the limit is 450cc. So I suggest you get a 426 kit. Or something similar if you already have suspension.
Where are you from and where are you racing indoors? The only indoor track I know of in Indiana is the motoplex, about 30 minutes from me. Where do you plan racing outdoors this coming season?
2005 450r - Janssen, Axis, Lonestar, Hiper, Maier