Shimano - Sram Crankset compatibility

ressac

I have a Trek 1.2 with an Ultegra SL crankset installed and i intend to buy a Quarq powermeter (on a Sram S975 crankset) like this: http://www.quarq.com/store#sram_130_/_110_bcd

Are there any compatibility issues? Do i need any other components?

Pokerface

You'll need a new bottom bracket. GXP one (all of about £20).

ressac

Thanks!