Is all the adjustability necessary?
If you're a beginner, no, it will confuse you.
If you're a top club racer, no, still not NECESSARY, but may help.
If you're a regional racer/sponsored, maybe, it will PROBABLY help.
If you're pro, yes, without a doubt.
I'd say if you are in the first category, get something like a Tamiya TA05 or HB Cyclone S, or the X-Ray T2 Pro. They have a lot of adjustability, but also are quite forgiving in that the set-up doesn't have to be perfect to keep them driveable.
Most of the rest of the set-up features the T3 has over the above is wank-factor to the average racer. Most guys don't know how to set them up, and get it wrong, and it ruins their enjoyment of the hobby.
I have a HB Cyclone TC that has 99% of the adjustability of the T3 (no on-board castor adjsutment), and I go with web-site set-up's and only tune the basics like shock oil, springs, positions, camber and castor.
Tyres have the biggest effect on tuning anyway. Get that sorted and you'll be climbing the ladder fast