Hello. I have 2000 convertible Corvette and need to replace the rear tires. I think that I would prefer to put non run-flats on the rear to save some money. Run-flats are $600 and nons are $300. Will this effect the performance a lot or the safety? I can't imagine it would be a huge difference. I always thought that the tire shop was just trying to make a sale because they could never give me a decent or intelligent reason WHY it is better to match the tires......Thanks.