Not that it's been a problem for me specifically, but my neighbor across the street who backs up to a field had this problem with his old Corvette. He said putting lavender scent in the garage is supposed to work to repel mice. I looked it up and sure enough, it will.
I keep an open box of lavender scent Bounce sheets in my '95 and have lavender whatever those cone things are that are supposed to go in the bathroom scattered around the garage to keep them out of everything else. You only notice the smell when you first walk out into the garage. Open the door and it's gone. I haven't had any problems with mice in 7 years we've been here. Only problem is the wife might like the smell so she might be out in the garage more than she normally would have...
Later
When was the last time you *really* did something with your Z to call yourself a Z enthusiast?