For ping I think anything below 100 should be good. I ran a few test from the PS3 browser last night and was getting 12-14 down / 3-5 up / pings 55-70 (lower is better for ping).
I still think we should run some test with different quality settings, mics minimum, no mics. Standard for race setting and lower race settings.
Also I don't want seem like I'm picking on anyone, I hate to see anyone go, but I have notice on occasion that when we are having problems and Bo drops the problem have cleared up. I'm NOT saying every time, only occasionally.
It seems also that there are two different issues: sometimes the whole group is effected and sometimes just certain people are effected.
One other thing regarding ping times, they are not constant, the value can fluctuate depending on server location, server load etc.