what is the best type of discs to replace my rear drums with... how involved is it... how much will it cost me...

The best disc system is the 1LE setup. How involved?.. well, it really hasn't been done yet. There are several people that are looking into it at the moment. You have to modify the brackets on the axle, drill some holes and then start to center the caliper. How comfortable are you with power tools, and measuring? Wait a few weeks and see if anyone can give you some pointers.