I just had 2 12s installed today and it sounds good except i can here the trunk shaking. what do you guys do to stop it.

 

You need to install sound deadener. On trunk floor pan, both quarter panels, tail behind taillight (from the inside), and behind license plate. May be able to tighten trunk deck down somewhat with the adjusters under the lip. Also, check to make sure all bolts on the undercarriage are tight.