hmmm...

1) RWD
2) manual trans available
3) decent weight and distribution of it
4) very capable independent suspension
5) availability of replacement parts
6) large aftermarket support
7) large variety of engine swaps

stack that up against anything else with a KBB south of $2500 and see what you get.

if people weren't so self conscious in Miatas or scared of rotaries then you would see a hell of lot more hopped up MX-5s and FCs running around.