Oh the dreaded transmission!

Last year I made the mistake of buying a 92' SVX LSI on Ebay. Don't get me wrong, I have always wanted one of these cars. My daily drive is a 91' Legacy with 265,000 miles on it, it has been the most dependable car I've ever owned. So I was looking forward to upgrading to the SVX. To my shock the transmission started going out on the way home from picking it up. I was again shocked at how I got screwed on the deal, but that's another story. I was again shocked to find out how much the transmission was going to cost and how many problems everyone has had with it.

This is a great car, I want to get it back on its feet, but I have a hard time paying more for a repair than I paid for the car!!!

I have been reading a lot on this website, you fellas seem to know this car inside and out. I'm looking for a little advise. Where's the best place to pick up a transmission (Cost effective and reliable)? What kind of mods need to happen to make the tranny last? And does anyone recommend or has tried the 5-speed conversion?