Hi folks,
Only just seen this as I tend to look on the S3 forum, but I have a TTS so can provide a little insight for you.
The TTS is a very different animal to the other 2.0T TT's, specifically in the engine used.....all other items such as the RNSE etc can be retrofitted very easily to any model relatively economically.
If I were you, I would decide what you want to do, buy a nice quick TT which can be modified and tuned to equate to a standard TTS, or buy a TTS for the hardware you get and the relatively unlimited tuning potential.
The latest TT's have the new 2.0TFSI engine which puts out approx 210 bhp and provides a lot of mid-range torque to provide good acceleration where you need it for day-to-day driving ( overtaking etc ).
The TTs however has the same engine as the S3 which is the older verion of the 2.0TFSI.....it is a tried and tested unit and has 270bhp as standard in the TTS ( slightly more than the S3 due to the better exhaust routing ).
You can spend a similar amount on tuning for both engines, and in the newer one you will have approx 250/260 bhp which is the starting point for the TTS, but with the TTS, due to the larger turbo and tougher internals, £400 will get you a stage 1 tune and provide 310 bhp very easily.....and that is TTRS/Porsche Cayman performance. From there, the sky really is the limit bhp wise.
I agree with the comments about the magnetic ride, which comes as standard on the TTS.....it is largely irrelevant on the road, but the standard suspension is pretty compliant for a sports car which means mag ride is largely for track day junkies or German autobahns !
It would also be good for you to take a look on the Audi TT Owners Club forum (
www.ttforum.co.uk) as they have specifications and FAQ's for the Mk II TT's which will answer all your questions.
So in summary, I would take both cars out as they are quite different animals, and you can then decide what fits you best.
hope that helps.