Hi Kristor I just sold my V8 for a 3.0 ltr Soarer, V8 noise is nice and it is quick, only had a quick shot of TT and it scared the hell out of me, though you would get used to it.
Opinions on the 3.0 ltr having had it now for 2 weeks. The one I have is a low mileage well looked after one with a rare japanese serice history. This was a contributary factor in going for it. It aint no slouch when you push the pedal down, not being that much slower than the V8 and in general the road holding and feel is better than the V8, air bags ideal for comfort but can get a little walloay on cornerning. Fule consumption still working out town figures but at 65 mph will give 32 mpg. :D
Engine parts easy to source as has already been mentioned for the 3.0 ltr the V8 though the same engine as LS 400 does not share the same alternator, (as I found out on getting parts for recon), power steering pump is different from LS 400 ( but can be modified to fit). If and when the power steering pump on the V8 leaks the fluid goes into the alternator.
So to summarise:
I would not be put of by the 3.0 ltr and its a pity its the 'lesser soarer' as it still turns heads as it goes by and still gives a nice exhaust note. And still can give some fun if desired
The V8 is a reliable cruiser, fast, comfortable, but air bags are expensive if they need replaced.
The 2.5 TT the hooligan of the bunch lots of fun and power, proven reliable engine, but get turbos checked before parting with money, Recomended to get one of these with traction control, if you can find one.
As has been mentioned, have a look around and try out all models, before you make a decision. Hope this helps good luck in your search.
If I may be so bold you could check out www.toyotaimportsforum.co.uk for a wider soarer view. ( hope this link permitted by moderator if not sorry)