the track wasn't wet, their wipers wasn't even on, the track was just damp from a humid day. the S2000 and the 350Z hand no problems with it, and neither did the porsche boxter. only the M3 was slide happy, however even you stated earlier is that the M3 was tuned to slide around alot. so there was nothing truely wrong with the track, as the S2000 was known to oversteer at the limit too, and the S2K showed no signs of over steer on that track. as i stated earlier, the M3 would be beaten by a NSX S zero. and the GT-R beats the S zero 4 out of 5 times.
you can be skeptical all you want, but the GT-R is much much faster then the M3 even in the dry. the R34 has the M3 beat in aceleration, in handling, and in stops just as well if not better. they have very similar weight as well, and the GT-R definitly makes more power then the M3.