I like your "do it yourself" attitude, thats the way I am with most things.
If you want to play in this game, you have to buy good parts, plain and simple. With the power your making you shouldn't be going through trannys like underwear.
- To get a good tranny, expect to pay about $2,500 that can handle 600-700 RWHP
- Get a 9" or 12 bolt and call it a day, also upgrade your driveshaft or that will break next
- Sometimes you have to know when you have to pay someone else to do some work for you
If you want to ask me a few things or bounce a few ideas off me, give me a call, I've been around these cars since 2000, I know a thing or 2.
Bill