I have a 2011 Outlander with about 85,000 miles. It's in great mechanical shape and no rust on the outside, but underneath there is, of course, quite a bit of surface rust. Nothing rusting through anywhere, fenders and quarter panels are good. Does it make sense to have a body repair shop sandblast underneath and spray it with a rust preventive paint or would that just be a waste of time? It's a great car and I'd like to keep it going for a long time. Thanks!