I want to put on HR rated tires and a tire guy says Saab wants a V rated tire.

SAAB engineered your vehicle with V-rated tires. Sure, V-Rated tires have the maximum speed of 149mph of which NO ONE will ever go. However, the more important part is the performance and handling of the car. Your V-rated tires are more responsive and have better traction than most H-rated tires. Any downgrade in performance/speed rating will change your ride to some degree. The question I have is why are you wanting to change from V-rated tires?