What car should i buy!!

Ok I need unbiased, or biased advice on what my next car should be )
I've got a few ideas myself but any other ideas are most welcome.
Firstly I should tell you that I expect to be keeping this car for at
least 5 years with the aim of making it into a show car, tweaking the
performance and generally making it immaculate. Also I have a budget
of £4,000 to a max of £7,000, will obviously spend more on it after
the initial layout over the coming years. Here's my shortist:

Mercedes 500 sec
VW Golf VR6 Highline
Porsche 911
Mitsubishi FTO
TVR TASMIN
Sierra Cosworth
Pontiac Fiero GT