Obviously these solutions should be car friendly!

Shouldn't that be "cat friendly"?

I've never heard of any damage to a car from cats. The other way round, sadly, yes. No cat would scratch the paintwork, or crap on the car, they aren't that way inclined. When you start the car, any cat is going to jump off, so what's the problem?   I suppose you might conceivably get a territorial moggy spraying on the tyres, but so what? Who goes round sniffing at the tyres on their car anyway?