[KTL]

Bill's original C2 brake upgrade is definitely the biggest and best approach with respect to rotor choice for these calipers. That is, if you're going to do it? Might as well get a rotor with substantial gain in thermal mass. The 930 rotor or the Wilwood HD substitute clearly accomplishes that with it's 20+mm gain in diameter and 32mm width. The other upside to using these rotors is the alloy hat (a rather simple one, which is also a plus) which provides a nice unsprung weight benefit when considering the heft of the OEM rotors' one-piece construction with iron hat. Using this front setup with the stock Carrera rear is do-able with the stock master cylinder, so that's a plus too. But as Bill said, the cost of converting the calipers is quite high.

A slightly lesser alternative is the VCI-type C2 caliper installation. Here VCI takes the modified C2 caliper and uses it with the single model year 1986 944T rotor. To use this rotor, you must to space it out from the A-arm a bit due to the higher offset of the rotor hat. VCI makes 5mm spindle spacers that are installed onto the spindle, behind the OEM collar that is pressed onto the spindle. If you don't use these spindle spacers, the rotor will rub on the A-arm at the ball joint connection. Some slight clearancing of the ball joint housing on the A-arm helps to ensure adequate clearance.

These small Brembos clear a 16x7 Fuchs wheel no problem when using the VCI adaptation This is another nice feature that avoids the switch of wheels for some people. As has been said many times in other threads, the 930 is the best fitter of them all- even 15 in. Fuchs can hold them. Like Spuggy said, a lot of people go straight to the top and get the monster setup. I think these small Brembos used with the right rotor is a good solution to a small problem with the Carrera brakes. By using a slightly larger front rotor, but not something so big that requires new wheels, and most importantly some ducted cooling that actually works, you can get your brakes well-equipped for track use without dumping a boatload of money. Speaking of $, one other thing I like about the small Brembos is they use the 930 pad, which nowadays is cheaper than the Carrera pad when you are buying race pads. Cheaper pad that lasts longer adds up to be a substantial cost savings in terms of your track event consumables.

BTW, the C2 front rotor is not the same dimensions as the '86 944T rotor. The C2 964 and the C2 993 (these two aren't the same either) have much more offset than the '86 944T rotor. These 911C2 rotors have so much offset, that some brake upgrade creations like those of Steve Timmons (Instant-G) actually install the rotor on the front side of the wheel bearing hub vs. the normal installation that has the rotor fastened behind the hub.