Looking for some thoughts and inspriation from the TZ crowd!

I currently have a Porsche 718 Boxster S as a weekend car. Its a great car in almost every respect, but I would feel a 4-seater (2+2 would be fine!) more practical and consequently I think I would use it more. The Boxster has only done about 1000 miles in the past 11 months!

I've done some reaseach already and formulated the following list of cars that under consideration...

Porsche 911 997 2S or 4S
Porsche 911 996 Turbo
Porsche 911 997 Turbo (stretching the budget here I think)
BMW 1M Coupe
Audi TTRS Coupe
Nissan GTR

I would like opinons on what I should be considering regarding any of the above models from an ownership perspective and of course welcome ideas of anything else of a similar vein that I have maybe overlooked. I have a relatvely small single garage so the GTR would be a snug fit to say the least, so nothing bigger than that. In the 11 months I've had the Boxster, it has depreciated at an alrming rate, so suggestions for cars that might not be quite so painful in this regard would also be very welcome! Budget would be upto c.£45k

Looking forward to your responses :)