Sorry, I missed the last couple replies. I do have factory head unit with Bluetooth mod via jazzy, I'm using a line level converter that's built into the amp, so it does adjust through the unit. It was a bit of a challenge, took me all day and I use to install for circuit city. The top spacer was the most difficult part, as the deck had several changes in elevation so I ended up doing a lot of shaving the spacer and recheck the fitment. As you can see there is only one tensioner(it came with 2) I removed the other as it would not fit, then I installed a set of springs to help lift and keep the trunk open. I used a pneumatic metal saw(like a jig saw) to enlarge the hole.the tensioner doesn't really rattle, but the rear deck was rattling bad so I put several pieces of foam to tighten it up. It sounds and feels great, but I think fabricating a long sealed box on the underside would likely yield a significant gain in overall performance(I estimate a third).