I forgot to mention I have the 20 inch rims, and the rear tire is a 315 and the front tire is a 265, so different aspect ratios mean you can't rotate front-to-back. At most, you could rotate them from L to R and R to L, which i suppose reverses the direction of the thread and minimizes some uneveness, but that is about it. The Conti thread pattern seems to be directional from what I see though. Right about now, wishing I had the 19 inch sport rims :-)
The DWS are made out of synthetic rubber, so I think they can be punctured !!!
I believve the inside goop will damage the TPMS sensors, but these ran about $80 in my previous car. maybe that is the best compromise.