I don't think you would want to keep the Blizzaks on all year round. Its a performance snow tire, and as a snow tire, you give up some things in dry weather. For example:

- The Blizzaks don't handle nearly as well as the Pilot Sports do in the dry. The sidewalls are softer and more flexible, and the deep but narrow tread blocks reduce the dry traction.

- The Blizzaks are noisier than the Pilot Sports because of their blocky tread design for snow.

- The Blizzaks don't wear as well as the Pilot Sports in the dry. The average treadlife is about 15k to 20k. Under normal driving, you'll get 3-4 seasons out of them if you only use them in the winter. Leave them on all year, and they'll be gone in a year to a year and a half.

So, its worth the cost and hassle to have them switched with the Pilot Sports each season.

 

If you're asking about driving with the Blizzaks year round forget it. The compound is made to be soft in cold weather for good snow and ice grip and will be like butter melting in the hot weather. As soon as the temps get above 45-50 degrees you better get them off or they'll experience significant wear and have substantially less grip than your OEM tires.

 

I know about the sand trick from when I had my 300ZX. That thing had no weight whatsoever in the rear. 1" of snow you would fishtail in every corner. The weight on the trunk used to work like a charm, made it feel much more stable.