Upgraded my stock 330mm 997.2 C2S brakes to 350mm Girodisks floating rotors all round. I re-used my rear calipers (with a Girodisc's spacers & longer bolts), but installed brand-new GT3 six piston front calipers with appropriate factory hardware up front. See below for the caliper hardline part number that works perfectly to connect the stock 997.2S's flexline bracket to the GT3 caliper. Bled the whole system with Motul and so far I've done 2 trackdays and 500 miles of street driving. So far so good.

Here's the parts list (other than the Girodiscs):
Part Number Part Name Price Quantity Total
9A7-007-585-00 Caliper Mount Bolt $2.99 4 $11.96
996-355-581-9B Brake Line $15.17 1 $15.17
996-355-584-9B Brake Line $15.17 1 $15.17
997-351-947-01 Brake Pads $210.50 1 $210.50
996-351-431-90 Disc Brake Caliper $898.43 1 $898.43
996-351-432-90 Disc Brake Caliper $898.43 1 $898.43

 

the 991 c2s 6 piston calipers are about $300 cheaper per caliper than the 996/997.1 gt3 calipers. They are not the same and have a different design though.

 

This is exactly word for word what I did. In addition I installed all 997.2 GT3 fender liner ducting and GT2 brake ducts. With proper brake fluid, you'll never boil your brake fluid on track again. It completely changed how I tracked this car. Haven't been on track since 2019 though

 

ATE 350 rear Rotors, 997TT rear calipers, 27mm M/C installed, brake fluid bled, PCCB coded, nice upgrade .. me happy, thanks rennlist for support

Klaus

 

Did you had to bleed the ABS after switching all that gear?

 

Vince, it was on my to-do list anyway, not sure if it would have been necessary tho

 

Recently upgraded to GG rated Textar 2551901 pads in the front and bent 16cm hard brake lines to replace the too long 991 ones, perfection

Laters
Klaus

 

Great info in this thread. Since it’s confirmed that 991 calipers fit, is it safe to assume the rotors would as well, or are they a different hub offset? Thanks!!