Daniel, was that car using the Mobil 1 and 300V a track car only... IE change after every day/race or was it a road car?
I asked this question to the old bloke at Advan one day and he said in their race cars they use 300V, they just drop the oil after a meet. (Race cars are on E85). He waffled on about the 300V 'turning to jelly' but I have yet to see this happen in my own car.