I don't know about in the UK, but in the US NA models cost way less than the turboed models. Best bang for the buck here at least is getting an NA model and bolting on a turbo. This is refered to as NA-T for Supra owners. checkout supraforums.com and na-tclub.com

A few disadvntages with an NA-T VS TT is that is your stuck with a 5 speed vs a 6 speed.The gears are prone to failing if your looking for over 400HP with the 5 speed. The wheels on an N/A model are also smaller than the TT: 8" VS 9". And finally if your mechanically savvy, the intake manifold has a tube that runs above the valve cover on an N/A model. This makes changing spark plugs, and taking off the valve cover less convenient compared to the TT where the manifold just goes straight down into the intercooler without making an overpass on the valve cover.

Are there any Supras that don't have a riced out body kit in the UK? lol