You can order directly from BC Racing North America Headquarters which is out in Florida. I'll be buying a set to replace my girls ST V1's as soon as I get back from overseas.
Their are a couple well know sponsors on this site that sell them as well for about the same price. I spent hours calling/finding the best place to buy these from. If you want I can PM you the info.
2011 997.2 GT3RS 3.8 - Sharkwerks - EVOms - GMG - RSS - Moton D/A
2009 E92 335I / 6MT - DPE - H&R - PROcede - AR - HKS - BMS - ER - (Daily Driver)