Surprizingly the white ones dont get very dirty at SoCal, they stay pretty white
I'm only running mod, but they are basically good for 1 raceday before you have a ton of slop and a nice notch.
I've got a lot of new black outdrives, so I'll just mix and match until I find a set that seems really smooth, but then again, it could have just been 1 bad outdrive that I got origionally that wouldnt run smooth.