I've never understood this visibility compliant about the TT. Or any size complaints. I'm ~6'4 and fill up the interior of TT- however its never felt cramped to me at all. On the contrary, I feel like its one of those cars that looks small outside but feels big inside.
In terms of visibility, I think it's brilliant. I have no blind spot at all with properly adjusted mirrors - making the car a convenient joy to drive most of the time.
I've had my TT for nearly 10 years now. It's been used as a daily driver, a weekend toy, a paperweight..
If anything stands out as a drawback to this car, it's the fact that it feels like a show car you can drive. While it sounds awesome (and it is - I never got tired of getting into that practically bespoke interior) - its also pretty finicky. Little things break - like the latch on the glovebox door, or the cup holders, or the latches on the first aid kit/cd changer compartments, the cd changer, the cell phone antenna, the license plate lights on the trunk, the headliner, etc... And the problem is a mathematic formula that looks like this:
small part failure x expensive costs for replacement x limited supply + the time spent tracking them down and replacing them
As far as drivetrain, it's fairly relable - especially the 225- however I have learned that the tranny is a time bomb. The shift cable tend to loosen up - especially with aggressive driving - which can lead to some crunchy shifts and eventually a broken shift fork.
So you need to be vigilant and pro-active with your maintenance.
But don't let all this talk you out of he car, it's meant more as a lesson learned to help you get the most out of it
As for mods, there are lots of options.
1. Bigger turbo ~$2000
2. Haldex tuning (~$1000?)
3. ECU ~$600?
4. Suspension
despite any issues I've had with my car, I till love it.