Suzuki LT F250 4x4 - Wheel and Tire Search

[ZukiQuad]

I have a '99 Suzuki LT F250 4x4 and it runs great. I really like this quad, right up until it comes to looking for aftermarket parts. I would like to fix it up a little by putting a different set of wheels on it and a good set of tires. However, it has 10" rims with a 4/140 bolt pattern. Anywhere have a good idea where to find rims with a 4/140 pattern?
Also, I have to keep the tires in the same ratio so I don't screw up the 4x4. Currently it has the original 25x12x10s on the rear and 21x8x10s on the front. Finding the 25's for the rear is easy, finding a matching 21 for the front is near impossible. Again, any ideas?
Finally, looking for a muffler. Mine has a hole coming in it and I would like to upgrade it. I have already put a performance kit in the carb (stage 1) and just want to clear out the exhaust.
Any help where to find parts for this quad would be greatly appreciated.

[KfxMojaveMan250]

You may want to check out motosport and they have specific parts for specific bikes and for the exhaust if you want a cheep one you may want to look for it on ebay. Hope this helps