I have found a great deal on a great set of tires..only hitch...is the load rating is a 89 not the recamended 91,,I assume this would make the suspension work harder,but to what degree i dont know..can some let me know if i would be making a huge mistake..and ruin my car..

 

I'm not an expert but I don't think it's generally recommended to go lower than specs. Higher but not lower. Although, I don't think the difference between 89 and 91 is more than about 70 lbs a corner.