Has anyone had any success in quieting down the engine noise in the cabin? For a little 4-cyl it sure is loud. I was thinking about putting some sound deadening material on the firewall and under-hood to see if that might help. The road noise is also quite loud, but I'm assuming this is something I'll have to live with. My 2004 Silverado with a 5.3L V8 is quieter than this thing.