I,ve got 15" R1R's and have now done just over 3.5k on them. I used to have 13"MB's with 888's but got fed up with the poor mileage. These tyres compare very favourably with the 888, the big advantage is in the wet - awesome! I drove through France last summer from Le Havre to Bergerac in torrential rain all the way and it was possible to cruise at 75 on the autoroute and that was with standing water, had I been on 888's then no way. They grip in the dry the same as 888's but I only use my car for road use, how they would be on track i don't know. They also grip from cold unlike 888's. The wear rating is 140 compared to 100 for the 888. They also have 6.5mm of tread compared to 5mm with the 888. My rears have now got 5.5mm tread left, the fronts have got 6.2mm. BTW my power output is 230. Basically very pleased and I doubt I would go back to 13" unless they bring out the R1R in that size.