The 996TT is just about the only car I would sell my 94 NSX for (my 00 will never be sold, ever!). Absolutely no desire to own a Ferrari or Lambo. i daily drove my 12 Cayman R for 1.5 years and that experience hooked me on the build quality and reliability of the Porsche brand. Not sure the 996TT is more practical than the NSX, but definitely think these are 2 cars that can be driven everyday without worry, unlike the other exotics.
I was looking at getting a NSX a few years ago, bought a 996tt instead. Had it about a year, recently sold it b/c my wife needed a new SUV as my 911 was just sitting there in the garage most of the time. Now I'm kind of tinkering around again with a NSX, S2000, or even an Integra GSR!
The 996tt is a great value, but as with all 911s the thing that is killer is the maintenance, esp the older ones. If anything breaks, you're looking at major dollars. Porsche parts and labor are NOT cheap. For example, during the time I had it for 1.3 years, with me driving it only 3k miles, I had to the following:
1) oil change $240 at an indy (takes almost 10 quarts!)
2) replace water pump/engine mounts/tranny mounts/serpetine belt - $2400 at an indy
3) Headlights suddenly went out and I had to replace the headlight switch $150 (I saved on labor as it was a fairly easy DIY)
4) Rear spoiler started leaking - tried a DIY re-bleed with a friend, pain in the arse, didn't work. Porsche wanted $2k+ for a new spoiler kit, or I could have gone with an aftermarket e-kit that was ~$1300. I ended up not fixing this and leaving it alone.
5) 2 carbon fiber strips lifted up and cracked; Porsche wanted $900! for 2 CF strips. I also left this alone and opted not to do anything.
6) There is a known issue with some of the coolant pipes on the turbo coming off when the engine bay gets really hot, likely from heavy WOT or hot day track driving. Indy shops wanted $4k+ to weld these pipes together. I never had an issue with this, but it was on the back of mind.
6) Through out my ownership I noticed an intermittent shift from 2nd-3rd that 3rd gear wouldn't engage for some reason. Indy couldn't figure out why and could never duplicate it; not a major issue, but I got scared of needing a tranny rebuild or having the need to take apart the tranny.
Owning the 996tt was a bucket list item. Blast to drive, great steering feel, legendary Mezger engine, great visibility and connection to the road, gobs of throw in the chest power, and I got great compliments many times (usually from young boys while dropping of my kid at school or older guys on the road). But I started to get scared of the maintenance and repairs, considering how much $$ I had to continue to fork while the car mostly just sits in the garage. Plus many major maintenance items require an engine drop, which is $$ in labor. Who knows, I may later get another 911, but just be aware. YMMV.
Would be interested to hear how much others have spent on NSX's maintenance...