From what I hear, Mugen Super grease is the grease of choice for centax thrust bearings. You can use Associated black grease also, which is what I have been using on mine since I bought the kit. I have a Kawahara thrust bearing as backup though.
RCNUT should have some univerals in this week sometime I think. I was going to order some from him earlier, but I need some driveshafts now. I broke my turn buckle rod on a hard crash due to brake adjustment. Then I lost a driveshaft.
G4 is really tough, I just hit the wall really hard this time.
That rear aluminum brace and carbon shock tower is an excellent upgrade. It really stiffens up the rear end for ya.