you can't say the miata is only a 2 seater and that it falls short of the s2k on that premise and that alone, last i checked the s2k is also on a 2seater.
bang for you buck, miata, no doubt. the engine can be turbo'd as is boosting power up to 250hp without any issues. it's handling is amazing, the aftermarket from mazda and other companies is very strong, and most of all a 95 can pull upwards of 35mpg. btw: all convertable's with the roof up have very big blind spots.
i don't like toyota or toyota products so eh on those. if you had to, i'd say mr2 turbo from the early to mid 90's. they can be had for around 5-8g.
how new are you looking?
Porsche 968:
Pro's: performance
handling
looks
rarity
all around usefullness
mostly 6spd manual
very nice interior
power everything
Con's: expense of some repairs
crappy tiptronic setup on auto's
back seat for kids only
for being a rwd, it's pretty good in snow with proper tires(no toyo proxes types) has about as much power as a honda s2k(about 240hp and 238tq). as a Porsche, its part of a community of people who help in most every way possible. it's all around practicality is amazing, the hatch design allows for food shopping and yet you still can go to the track on the weekend(wouldn't suggest dragway). though their warrenties have run out by now, relize over 90% of all porsche's produced from 56-now are still on the road, so they aren't shitty build quality. the aftermarket for upgrades is amazing, from turbo's to suspension and brakes, everything you can imagine is there.
don't go for the turbo s versions of these, as only 16 were produced and command up to 60g, the turbo rs, only 5 and around 75g(only cause they were raced an abused). the CS(clubsport) very good combo of lightweight performance and creature comfort.