With regards to your comment about the MX5 being a womans car, well some of the later cars are bought by woman who don't have a clue about cars but just want something that looks nice.
However the majority of Mk1's are owned by blokes who are true car enthusiasts. About the cramped cabin, well its aint! I'm 6 foot and I fit fine, if you were any taller then yes leg space could be a problem but at 6 foot with the seat fully back its no problem at all.
I'm sure that if you gave a mondeo to say, the Stig, he could beat any of us in an MX5 or smart roadster for that matter, it all depends on how far you push it. However, its more about how it makes you feel, and the feel of the steering combined with other things. But one thing I can confirm is giving a decatted MX5 a blast through the revs through a tunnel, well theres not many better sounds your gonna hear than that!