From all the forum discussion, it seems that the GTO's problems with wheel hop and associated "thunking" sounds from the rear end on hard acceleration are due to having an independent rear suspension (IRS) instead of the old solid rear axle design. However, I haven't read about any such problems with the Mustang Cobra, which also has an IRS and a good deal more power than the GTO (390 hp). Anyone know why the Cobras apparently don't have this problem (stiffer springs, different tires, perhaps)? Is the Ford IRS design significantly different from the GTO? Is so, is there anything we might be able to take from that design to fix the problem on the GTO?