Hi Chet,
Trail friendly.....best kit .... I don't think so. My best advise would be to buy your BB kit from someone who will be able to help you set it up correctly and more important continued support. Lots of discussion up front regarding the fuel you plan to run, head design, pipes you plan to use, clutching, additional cooling, proper jetting. Several companies made kits but few will spend time to support. And remember these sleds are 15 years old so support is thin. PM MRViper700. He's got what you are asking for. Lots of experience.
---mac---