This may sound like el-cheapo corner cutting, but budget constraints can work on you this way.

For starters, I'm surprised I'm having balancing issues with the new wheel/tire combo on Bonnie. My local shop guy (who has extensive experience with this)has now tried 3 times to iron the problem out. The car is absolutely fine until you reach 65mph and then the seats start to shake. One back wheel took quite a bit of weight to balance, and the vibration is more annoying than anything else, but with the stock rims/tires the car was plank smooth to 80mph or above...so why not now?

My feeling is that the tire is bad, but the eBay store I ordered them from (buywheelstoday) wont take a return if the tire has been mounted (so how the heck do you know if its bad?)

I sent them a stern discontented email, but I doubt it will change anything. I'm considering swapping the tires to the convertible and see if the issue remains, but that also means I need another set for Bonnie.

I've noticed several sites that sell used tires, and I began to wonder if it would be worth getting some second-hand high-end tires,(like Michelin Pilot Sport A/S)

The high UTQG rating still offers long treadwear, and as long as they have no patches or plugs they should be good.

Part of me feels like this is splitting hairs, but the most inexpensive set the local shop offers is over $700/set (and thats for a low end tire) Pilot Sports retail for around $240 each when new, so a price of less than half that doesnt sound bad.

I guess mostly I'm just hacked off right now that I spent the bucks for the wheel/tire set-up I've got and it looks like I'm eating at least one of them for lunch...and that tastes like crap.