Food for thought..there is no reason why you should wad up your car cause you were trying to get your money's worth doing a double (8 runs at 20 minutes each). You will get tired..physically and mentally. I personally wouldnt do more than 6 X 25 sessions. You can tell when you are tired...missing your apexes..tires getting greasy or overinflated...all of a sudden getting a nasty push... Live to fight another day.
