LarryC:H's are more comfortable than 150 mph V-rated's IMO.
Some places like tirerack.com won't sell H-rated tires for cars with advertised top speeds that warrant a V-rated tire, even if the customer declares he/she has no intention of driving that fast.
I beg to differ about that. After the OEM Michelins on my Dodge Grand Caravan wore out, I planned to get a set of H-rated tires, but my friendly tire dealer (Cheap Thrills, in Milton, Ontario), suggested the Bridgestone Potenza 730, a V-rated tire, since he knows I'm an enthusiastic driver and would appreciate the improved handling. I didn't need the higher speed rating with the low limited speed of the mini-van, but it seems that the stronger carcass of the higher-rated tires means they have stiffer sidewalls, which results in a lower slip angle, or in layman's terms, a more immediate response to steering inputs.
I was prepared for a rougher ride, but was surprised to find that it was just as smooth as with the Michelins, but the traction and handling was much better. Even passengers noticed and commented on the sportier feel of the vehicle.
Tires have a wet traction rating marked on the side, usually A or B, but the 730s have an AA rating, and it's easy to notice how well they grip when driving in the rain. When these wear out, I'll be buying another set of V-rated Bridgestones.
As for Tire Rack's policy, they are completely correct. If they were to sell tires that didn't meet the car manufacturers' specs, it could be dangerous and could leave them open to legal action in the even of a tire-related incident.