Look for an AE71, it will make your life a fair bit easier. It isn't hard to modify a KE70 to run an A series motor, but it is a bit of stuffing around that you can avoid if you just get an AE71 to start.
Depending on how much you can get an AE71 for, you should be okay for $8000 if you do a lot of the work yourself and you don't go crazy.
So yes, the two big things you'll need to go out and buy now, are an AE71, and a 4AGE (or GZE, depending on what you are after). Once you get those two, then you can start fiddling and getting all the small things together.