Hi Matt and welcome to the club!
Generally people start with a full car if they've never driven a supra before, it would be a bit of a heart ache to waste a couple of years and spend a fortune building something that's not really what you expected. Not that that's the case they're lovely cars and most people that drive a supra find it hard to better it with something.
Find something that's best suited to you and get the feel of it, then if it's everything you expected you can start thinking about upgrades etc but usually it's always best starting with something as a whole, that way you can sell bits to buy bits you know exactly what's what and you'll save yourself a whole lot of frustration in the long run.