i have a Griot's dust car cover for my G but ended up not using it much. thing is i have a battery manager hooked up to it (hood not completely closed, cord dangling) and also i like to sit in the car from time to time while hibernating.
it's the same way for my Z so i decided not to get a cover for it. my garage door doesnt open for a few months once both cars are in hibernation so not much dust to begin with.