DD -
Last year when I did my build, I installed a Kennedy LWPP and this disc:
http://www.patrickmotorsports.com/pa...-racing-sport/
However I got the disc at clutchnet.com for about half the price Patrick sells it for. (Clutch.net 6BS7021 $165)
It's got WAY more clamping force than my old rubber center disc but its awesome on track. Not sure I'd want to daily drive it tho.
Make sure you do the G50 shaft fork update and new throw out bearing, etc.