I dunno. I've been in and out of this hobby for over 20 years and have just recently had a real interest in TC. I've been keeping an eye on what's out there and what's in the pits. I suppose its a money pit if you let it get that way...
So while it is *possible* to get away with a $150 kit, something like a Cyclone S or a TT-01, or use a $150 BL system, or Orion's 2400 lipos, or a $70 AM radio with one frequency, take a look at the pits, are a lot of people using those setups? Would you actually recommend that to a friend who wants to race competitively?
If you listen to some advice given by veteran racers, most will tell you that you *might* be competitive in novice with that setup, but probably not anything higher. If you're thinking about a TA-05, might as well get an IFS or even an IFS-R, it only costs a bit more and you get all this bling! Oh, and the stock tires are crap, you'll need these. The 2400 battery isn't gonna be enough, you need this. Don't get a cheap AM radio, you want 2.4. And so on and so on. Sayings like "buy cheap, buy twice," "you get what you pay for," and "you only live once" don't help either!!
Spec racing is a nice idea, but what ends up happening is all the veteran racers start "joining the fun" and thinking "surely I can win this class," and with their great tuning and driving skills, they quickly overmatch the beginners that the spec class was designed for in the first place! Oh the humanity!