Engine mods. Who’s the best?

Ok it’s time for a big bore kit on my 2000 400 exc. Who does the best for the money? I’m looking to go up to around a 450 set up for the woods.

Also some transmission work. I have a counter shaft that has too much play. (When parked in gear, roll bike back & forth I get about 3 teeth roll from stop to stop on a 14 tooth counter sprocket)

I also have a small crack I need welded while the case is split. So I’m looking for a company that can do it all.

I live just outside St. Louis & would be nice to find someone here but shipping is no problem. I really don’t have the tools or the time to tackle a 4 stroke.

Any comments would be greatly appreciated.

Thanks,

Mike