Why do you have to replace your exhaust, clutch etc.?

Did you damage them?

If not, the stock exhaust, clutch etc. works out just fine in the ntc3 and the mt 12 and os tr .12 in my opinion are the best bets, I had a friend with a pixi .12 which I believe is rated at around 1.6 hp, but the mt .12's and os tr .12 are just as fast.

You should be able to find a new mt-12 or tr for around $125-$140, I've seen them pop up on ebay now and then.
http://cgi.*********/ws/eBayISAPI.dl...category=19168

here's a great deal on a used tr .12
http://cgi.*********/ws/eBayISAPI.dl...category=19168

It just dawned on me that maybe you don't currently have rear exhaust but even if you needed new exhaust, you should be able to easily stay below $225...