The aero testing done by a bunch of guys with older nissan z's showed venting does a bunch for aero. Vented hood and fenders made a huge difference in drag. Pretty much a must do.

It was discussed and linked to here but I didn't favorite the page.

Nice looking car bbundy. I enjoy threads like this even if my car will probably never be on a track.

What about the ISC air dam/splitter?

http://www.iscracing.net/images/0miataair_dam1.jpg

Miata Air dam

It's a nice part but not wide enough for most of the guys running 15x8 or 15x9 wheels. Also once shipping is figured in it's pretty spendy. It's built to specs limited by the SCCA. Most of the track guys here are running time trials or just for fun and don't have the dimension limitations that part was built to.

Say when...

i have been thinking about that bumper. it actually is wide enough for most of us. it takes over where the factory bumper starts to taper in.

this was my ISC setup with aluminum splitter.
ISC air dam broke in half first day on track. it is super fragile, being fiberglass.