A big advantage of getting the kit from Speedtech is Steve's supplimentary sheets, detialing the tricky bits. The photo's are quite good for building the kit. JDM has done some work on translating the instructions, maybe he'll be able to help, when he's not polishing his 6 cars
I have stuck with the long suspension arms, I don't want a super agressive car, I can get a good setup fairly easily most of the time, infact if my setup is bad it's probably a problem with the car, namely when I had a little diff problem or a screw has loosened itself somewhere.
I leave as little play in the diffs between the bulkheads as I think is sensible without it being a tight fit, maybe enough for just one more shim to fit in but be snug against the bearing and diff. The diff gear mesh I've been experimenting with, the teeth are big enough to leave a large range possible for the mesh. I have it now so that there is about a millemeter of movement in the diff gear when I hold the smaller shaft gear still, a bit like meshing a spur and pinion.
If you've read this thread you'll see that getting the shaft aligned well is important, check alexracingusa.com for good building tips. The better the alignment and mesh of all parts in the drivetrain, the quieter it will be when you run it. Running without the diff cases also makes things quieter