Here's some interesting/useful info I've just read at
http://clubroadster.net/vb_forum/showthread.php?t=55555 that may influence your thougts on pads:
"The Carbotech SM package includes:
Full vehicle set of rotors (Front and Rear OEM brake rotors approved by Carbotech for use with their pads)
Front Carbotech XP10 Front Brake Pads and Carbotech XP8 Rear Brake Pads
This package is set up for a track only road racing Miata, such as a Spec Miata. The XP10/XP8 combo has been proven to be the best brake choice for most people racing Miatas, the XP8 is a slightly less aggressive compound and is used on the rear to bias the braking, as bias is not adjustable manually. Spec Miata's benefit from a lighter rear brake to avoid rear lock-up under extreme trailbraking conditions and rain racing.
For your car, I would suggest either the Carbotech 1521 compound or the AX6 compound on all corners. The 1521 is Carbotech's street/auto-x compound and the AX6 is a more aggressive auto-x compound that can be used on the street with the side effects of a little more dust and low temp squealing. We use the 1521 on our street Miata and it is a very nice pad that will outlast your vehicle, and is extremely easy on rotors.
If you want a bit more bite, I would step up to the AX6 unless you are overly concerned about dust and noise (although not nearly as much as the comparable Hawk HP-Plus pads, which are harsh on rotors and put off tons of dust). These pads would be ideal for auto-x and will work great for weekend driving.
The Carbotech rotors that come with the package are not cheapies, but an affordable OEM replacement, however they have proven themselves on our Spec Miata's and many others to be known good racing rotors and worth the extra couple of bucks. I would be wary of extreme cheapies, we've used $20 rotors from NAPA before and took them off after one session because they felt like they were covered with oil (yes, we did wash the oily residue off before we used them!).
As for the other choices out there, they might be cheaper, but from what I've noticed the difference has been in the rotor wear. When we used Hawk products, we tore through rotors so fast, at least 2 or more sets a season, about every other brake pad change. With the Carbotech pads, we can make it a whole season (at least 10 weekends a year) or more on one set of Carbotech rotors, which made up for the difference in price of the pads over options like Hawk. The choice is yours of course, but that's why we use Carbotechs (plus they are awesome for not locking up tires under trail braking, which is important in SM).
I can get some other options for you as well if you're interested. We have Hawks and can get Axis too. I will put together kits like the SM kit for these pads in the future."
) but the pads just fabulous.
