its actually a rather easy build. id say around a 3 with 1 being easy and 10 being hard.
the instructions are very well laid out and easy to follow! this really makes it pretty easy. the packages are well labled, though a bit weird in layout.
the parts are easy to work with cuz they are bigger, almost every bolt has a nylock nut on it. if you built/repaired/fixed any rc before, and can read english or japanese, you ll have a very easy time with the build.
to help you understand some of the process, how large it really is, and how easy it is, follow this link
www.hpibajatutorials.com Fast Eddy has made this Video Tutorial Site to help doing work to our baja. I believe he has a video series outlineing a SS build as well.
Have fun and enjoy. the Bajas are great. I have 2 heavily modified bajas myself.