Am I missing anything?
 

zzzz

S2000?
986 Boxster S?
944 Turbo (no top down fun though)
MR2 Turbo with money left over for modifications
MR-S Spyder /w money left over to swap in a 180HP 1.8L from the celica
BMW Z3? (the M model is probably out of your price range)
350/370z (the roadster is kinda squishy from what I understand, so that might be not a good fit)

Forgot the S2000. Too many junkers & lots of overpriced ones. Was looking at a few boosted for the 15kish & no proper tune, etc. Not a gamble I want to take.
I can't justify anywhere near what 2nd gen turbo MR2s go for.
Porsche maintenance & cost to maintain = hard pass.
Z3 doesn't interest me, but Z4 does. I almost bought one when they were new in 2005ish. Again, maintenance nightmare potential so no.
350Z crowd is as bad as the S2K crowd.

As for the maintenance of German cars, Is it really that much more than an aftermarket boosted vehicle? In the end; M.I.A.T.A. means Miata is always the answer... When Miata isn't the answer the C5 and C6 represent the pinnacle of performance bargains.

The problem right now is that a lot of the best performance bargains have skyrocketed in price.
Early NSX's used to be in the $20k to $30k and clean ones going $40 to $50k Today a higher mileage one is easily $45k.
Aircooled 911s used to be bargins at $15k for an S.C. today that car is $30+
Porsche 996's used to scare people away with the IMS bearing issues meaning you could pick up one without a documented service history for $10k and well sorted examples sold for C5 money. Turbo's sold for C6z money.