Pretty much everything is a direct bolt-in. I bought an ax-15, transfer case, and new clutch from a '90-something wrangler for $400, Bellhousing and hydraulic setup from a '95 cherokee for $35(I wanted the external slave), pedals and steering column for $60, new flywheel for $100, new computer for $300(don't know if I needed it or not) and a pair of axles with 4.10's already in them for $400. It took me about 40 hours to get it done. Had some issues with the original flywheel; the guy I bought the transmission off of told me it was from a '94, but it was from a '90. Different flywheel, the cps wouldn't read it right and I couldn't get it to run. I ended up pulling the transmission 4 times before I finally figured it out. Once I put the right flywheel in, it fired right up. Since I have about $6000 wrapped up in my Jeep already, I didn't want to have to start over again. I gained oodles of power right off the bat, and it increased my gas mileage, too. The auto read 2700 rpm @ 60mph; the ax-15 reads 1900 @ 60mph. I gained about 4 mpg, and the increase in power is nice too. I run 33 x 12.5 BFG's, and I can chirp the tires in the first three gears. SO much more fun offroad, too.