Retrosound, Amps & Sub Install

On the vibration you are getting from the trunk lid you have some options that won't require welding. One would be to get the adhesive like they use on the hood of our cars and start bonding the under bracing to the outer skin. Another option is to get a product like Hushmattl or dynamat. These products will take care of the vibration but they do add weight. My 70 Dart will get a full hushmat treatment before I put the interior back in. I hope this helps a bit.