One of the Harddog roll bars, some brake pads, and a tire trailer?
The shortcoming of the miata is that it is a bit cramped. Even with my Mustang I end up envious of people with hatchbacks that can swallow tools and a set of tires. However, there just arent many RWD options in hatchbacks and many dont like FWD/AWD for track work. I guess the closest thing is a BMW 318ti. The Miata would win over that due to the massive development that has been done on it in comparison as well as a much larger market for go fast bits (new and used) that would tend to drive prices down and prevent you having to invent your own solution to things.
In regards to the specific miata, it has a torsen and it is a later miata, some prefer the lighter weight earlier miata and see it as more tossable. The only detraction from the SE is that (if I'm reading the specs right) its something like 50lbs heavier, which could be stereo stuff and could also be that (IIRC) the torsen diff is heavier then a non LSD.
What kind of details are you really looking for?