Winter Storage Boxster S
 

I'm putting my '04 away for the winter. I'm going to change the oil, add Stabil, etc. My big concern is tires. I live in Massachusetts and it gets pretty cold in the winter. I just bought Michelin Pilot Sport PS2for it in August and want to ensure they don't flatspot. I've heard everything from jack up all four wheels (can I use cinder blocks?) to inflate to 55 psi.

I'd appreciate any real world advice. Thanks!