Was overseas for a while and had my 8 temporarily stored at a friend's... now I'm back, but the 8's still got the winter tires on, and lost the original (summer) performance tires in the shuffle.
Any advice on major disadvantages of driving around in summer conditions (Midwest) with snow tires??

 

You mean besides terrible performance, looks, and will wear them out in no time? no problem I could see!

 

I have been running Bridgestone Blizzak LM-22 winter tires since February. I purchased the car used at that time with about 28000 km (~18000 mi) on the clock. It now has about 34000 km. The dealer of the original owner says he put the winter tires on the car at about 15000 km.

I intend to run these tires until they need replacemant.

I think they look good.

I can't speak for performance since it is the first car of this type that I've owned. That said, performace in my opinion is awsome. Maybe I'll notice a real difference when I eventually replace these tires with all-seasons.

With regard to wear, the current tread depth on the tires is just slightly over 1/4 of an inch, but I don't know what the original depth was.