TA05 or TA05 ver 2. More than you will ever need in a drifter. Get the spool or direct coupling (as Tamiya calls it) for the rear and run a tight front diff and away you go!
Buying a more expensive chassis would be a waste unless you only drift and want all the bling
Oh and if you decide to give racing a go the TA05 is more than up to the task. I have wipped many a high end chassis with my TA05 when I used it for racing before it was a drifter.