macsdad 10+ year member
boom-boom
A good thing about Cadillac's is they are pretty well damped OEM, due to them being luxury cars. I can turn the volume up to 40 in my SRX, and with the doors closed and windows up there is very little rattle, and that comes from the over-hang above the rear window. I had a crazy rattle, realized it was the door for the ski-pass, leave it open, no more rattle. But you still may need to add a little to your trunk lid dude.Going in a trunk set up..Id go for an XFL 12 all day long or an HDS3 12. All the XFLs I have 10s and 12s have been nothing but straight up beast and very reliable for the money spent.Any sub in a trunk set up is going to give quite a bit of rattle to the vehicle unless you do some deadening.I have a 2.0 double baffle tuned to 32htz enclosure for a 12 ,that I utilize all the time with a DVC2 and or one my DVC4 and it serves very well.Id look at a decent 2krms amp or at the min of 1500 rms. Those subs eat every bit of either RMS power thrown on the daily.Great choice of a sub for trunk space.The HDS310s and 312s I have are the older version and do great as well. The newer 10 i picked up does fine, but doesnt dig deep like the older versions.The XFLs just get down and can sound very nice if you build the enclosure properly and 1k or more rms power