What Car ?

I can't help feeling M2's and M3's are just too dull and sensible for this brief, great cars if you only have access to one. But you have another...

997 911's (indeed all 911's) are indeed over priced, sadly, though that may be on the turn. Caymans make a lot of sense but from the 987 gen 2's onwards they take a huge rise in prices for very little benefit (a very sight chance of bore scoring becomes a very very very slight one, and they can handle serious tracking better). Gen 1 987's are superb value and half your budget for a great one.

Running costs are clearly a biggie, but things like F type R (or the P450 you have already) are somewhat sensible, before you get to Maserati's, R8's, and so on. It's becoming said too often but R8 V8's are superb value. Aston Vantages as well, though more money to run. I'd definitely look in this area if it were me, the better one you buy (and the sillier the engine) the more it will retain value, if that matters....

I’m not sure we can say that 911’s are overpriced. There are so many of them for sale it’s the market that sets the price and that’s what real buyers are prepared to pay (in the main). Running costs are pretty sensible, especially when you get one a generation out of date as they drop onto fixed price servicing and extended warranties are a lot less than for similar cars. Insurance isn’t crazy either.   All that helps keep the prices up. 

The 987 / 997 Gen 2 cars are worth the extra imho, the exterior changes make them look more modern, as do the interior parts like the screen and steering wheel.

Otherwise what about as late an XKR as you can get? The supercharged V8 certainly is a celebration of what's great about ICE and they seem less lairy (and more day-to-day useable than the supercharged F-Types that seem to go too extreme - which is why the P450 became the range sweet spot.

Very late XKRs have mainly been dipped in chav sauce (speed pack body kit and bloody black wheels) and feel quite different to F-types (in a way that you won't like if you enjoy the way later F-types go about their business). They also have a lack of traction that quickly gets on one's jelly ends and the 6 speed gearbox is a wee bit old fashioned. A facelift XKR coupe in Indus Silver or Kyanite blue with the standard silver 20 inch Nevis alloys is still an immensely attractive car though.

I did suspect this was maybe a pointless thread as the answer is clearly F-type - but that's partly because I get a stonking deal. However, I am slightly institutionalised as far as Jaguars go so I should make the effort to sniff some German roses.