It sounds like a good idea but most paint won't adhere the the plasic properlly and will chip off... It ends up looking like shit... Believe me I've tried.
Everything is divisible by metal- Michael Angel Batio
I don't know but if you are to do it try and remove the cloth or make sure it doesn't get on the speaker,it might not do anything bad to it but it ain't exactly gonna do anything good to it either,but I can't imagine anything bad happening so best of luck.