I second what Kane said. I just replaced my fronts at 17K but due to bent wheel issues. Still 6/32 on the original Conti's on the good part of the tire. Rears i am keeping, also with a good 6/32. I have not yet measured the depth on the new Conti's I put on the front (identical to OEM) but I believe I read somewhere that new they have 9/32.

I would say you could get 30K out of them, but the stars better be in alignment as well as your 4 wheels and I'd bet you'll be down to the wear bars, which is not a good thing to do anyway, especially with these cars.