I was in the same boat about 6 months ago. The main thing I was after in my next car was more feel. I wanted a raw experience and the TVR filled that gap perfectly. But in-between making the decision I must of looked at every sports car between the 15-20K mark.
Lotus - 6,1 I didn't get on with the space and lack of comforts
Porsche Cayman - Handling was incredible felt far to tame. The nicer spec was just out of my price range.
E46 M3 - Felt very boat like from the Zed but struggled to find a clean example.
Chimera - beautiful sounding Rover V8 Looked a little dated for me
Porsche 911 - Looked at high mileage 3.4s but didn't get a good feeling, felt a little under powered
In the end I settled for a TVR Cerbera 4.5 The styling was spot on and the driving is such a raw experience, it kicks and screams like a banshee under full load. Also no matter where you go people stop and ask questions and take photos.
Lee