after going through two t-5's, i'd recommend just going with a tremmec if you can afford it. with anything more than stock power the t-5 isn't going to last. if you choose to get it rebuilt though, i believe it cost me around $300 for everything
A T5 rebuild kit with syncros, bearings and other small parts costs about $160. It does not include any gears or shafts.
http://cartapes.com also has a video on how to rebuild your T5 or Tremec. It costs less than $20, and is worth every penny of it.The video was an immense help, and I would recommend viewing it. At $20, it will give you an opportunity to look and decide for yourself if you think that it is something you want to try to do.