I bought a certifies IS300 recently and the steeiring wheel wobbles in the morning for a few minutes while driving because the tires are cold. The dealer says it is because they are high performance tires so they "flat spot" until warmed up. I think this is a bunch of crap because I've had high performance tires on my Vette and they are fine? What else could it be?

Over night the tires will flat-spot just enough to make the wheel wobble for a coupple minutes but it's no problem. Vetts are COMPLETELY different. The tires are wider and lower profile (on most) and not comprable to an IS-300. I love both cars though and would be happy to take either off your hands!!