I waited 4 years to buy a Supra mate, plenty come up for decent money, as already said £6k should get you a minty mint NA or a very tidy TT auto. I would buy a decent NA for £4kish then save the rest for a decent TT conversion.
OR....
Buy and NA and a TT engine, drive the NA for a few years while slowly rebuilding the TT lump then drop it in. Perfect solution.
Have you got any quotes for an import TT yet? i found there wasnt much difference to be honest, fuel is pretty much the same until you really go for a hoon in the TT.
My TT was my daily driver doing 160 miles a week on about £50 with mixed driving, which was only a few guide more than my Leon Cupra R used to do! obviously if you have a heavy foot you will need shares in the local Shell station.
Also be aware that these cars are getting on a bit now and its not a case of IF work needs doing, but WHEN. Most parts easily available from breakers on here etc but some parts are still very expensive such as £700 for replacement suspension arms from Toyota.
Dont let that put you off, they are bullet proof engines, usual Japanese build quality and reliability so take your time have a good hunt around and get a nice one.