Thats just it. The Keyence range is so advanced, trying to get to grips with it is not really something for the feint hearted. Most people buy it and copy other peoples settings. I wouldn't bother getting it just yet. We been drifting for a few years and all of us run Keyence ESC and motor and not even bothered getting the TAO/Brain just yet.
I would say starting out, get the essentials and work more on technique. If you budget caters for the TAO, go for it but honestly with the Keyence range, its more of a fine tuning tool. Im running factory settings without the Chevalier boost cap and any sort of programming but its the smoothest thing ive ever used since the birth of the wheel alongside being able to keep up with some of the finest drivers who hit soul (not all just yet) but mainly its down to setup and technique. Not saying don't buy it but that sort of stuff wont really benefit you till later.
If you are starting up and want something that will serve you well and have a generous budget get the following
MST XX-D HT VIP
OR
You could go for the new MST RMX VIP but its super new, not all the parts are available in terms of spares and upgrades. Seems to be a lot more complex so for someone starting out, it might not be the best idea.
Sanwa MT4 or the M12 if your budget allows
Keyence ESC. Standard cap is good enough
Keyence 10.5T BS or non BS motor
As for your choice in Overdose shells, as long as its not the JZX100, you be fine. JZX100 is also made by HPI with the same detail etc as they are made in the same mould. ;-)