Does anyone have any experience with a performance exhaust system for a 2007 GMC classic with an lbz duramax that is quiet while towing. The last two vehicles I have towed with had performance exhaust and here it the mountains they were both too loud for the family to enjoy the trip. One had magnaflow and the other had Borla. The were both gas engines but had a terrible harmonic in the cab while under a high load. I have heard the Diesels are actually worese for this than a gas engine. Thanks, Paul.