Here's a good rule of thumb to go by: heat. Get yourself a tempgun. Tempgun.com makes a few good ones, I have one myself, and they really help. Your LHS should have some.
You do not want the temps on your motor (whether brushed or BL) to exceed 170 degrees. Anything over 190-200, and you're damaging the motor. Anything approaching 170 for the ESC, and the ESC is damaged. The best is to keep it around 140, less would be better.
Actually, since drift doesn't require warp speeds, you could gear the motor pretty low. Get yourself another pinion, say, a few teeth smaller (like two or three) than the one in the car now. It's also wise to get fans, and mount them on the ESC and motor, if possible. The Castle Sidewinder SCT has a motor fan. This is good.
I have a VDF myself, and it has a Castle system in it, that never reaches anything higher than 105 degrees. It's geared that low. There is no set size for the pinion/spur (except for racing, but you're not racing), so temps are what you go by. Pinions (yours will also be 48 pitch) are fairly inexpensive, and downright cheap, compared to replacing a damaged ESC/motor, so you could get a few of differing sizes, and use the one that gets you the low temps you want.
BTW, that Castle Sidewinder SCT is pretty affordable, isn't it?
If you have a fairly recent Windows program in your PC, get the Castle link too. You can then "tailor" the performance of the ESC to your liking.
Yup, the VDF and DRB are too expensive these days. I got mine before anyone here in the states even knew what a VDF was. Back then, you could get one for $270 (at RC Mart), but now???
That costcannot be justified. I've been getting mid - to high priced TC chassis and converting them to drift ever since. All those previously mentioned chassis would make fantastic drifters, so it's still a possibility. Shop around. I guarantee you - if you decide to stick with drift, you will WANT another chassis. TT01's are for novices, and I was serious when I said that high-priced chassis drift easier than budget ones. I wouldn't dump a lot of money into a TT01 (unless, of course, you REALLYlove it), when that money could be used to get a better-handling chassis.
You could look into these, too: Ofna JL10e TC and Drift chassis, X-Ray T2R. Any of those are affordable, and would make great drift chassis (I did up both JL10e chassis as drifters, and they both worked out VERY well - the T2R is next!
). Take a look around....you'll be surprised what you find!
Oh, BTW, all that is required to remove the pinion is an allen head hex driver of the proper size.