got my 30k service a couple days ago, and talked with my service rep about the problem... they didn't find anything out of the ordinary, and just recommended rotating the tires every 7500m, and doing alignment stuff a couple/few times a year. i guess it's worth it to pay an extra $150/year for a couple more alignments if it prevents spending $600 every 10k miles on new tires...

i guess we'll see!

thanks all.