Re: Soon to be GTV owner?
lots of good advice on the GTV/916 spider forum. look up the buying advice thread. That'll tell you the main things to look out for.
I was exactly the same as you in thinking I may as well have a good looking/ impractical coupe while I can before things like kids and probably tax soon make it impossible. and sod the extra insurance costs etc! Though with a couple of years NCB it's not as bad as you'd think even for the V6.
As for which one this perenial question, if you do a search you'll find hundereds of V6 vs TS and Spider vs GTV threads which run for weeks and invariably conclude that it's down to personal opinion/needs.
To state the obvious.
The V6 is faster than the TS,
the TS is cheaper to run than the V6 (by how much depends on insurance history/age, your mileage and how you drive.)
Some say the TS handles better due to the lighter engine, never driven a V6 so don't know.
TS engine is more fragile than V6 and it's more prone to suspension problems, V6 is more expensive to fix if it does go wrong and has it's own issues (oil cool pipes etc).
If you want a drop top get a spider
If you want a coupe or need some VERY small back seats get the GTV.
Again, some say the spider can't handle the V6 power so go for the TS.
Whichever you decide, make sure it's been well looked after with full service history. All the GTVs will run for donkey's years if looked after properly but a neglected one could be your ticket into a world of pain.