After Market Subwoofers

I was wondering if anyone has switched out there factory sub behind the seat for a new sub and whether that caused a lot of problems.

Currently my Z, an enthusiast model, has the black panel so I am going to buy a subwoofer and put it in the car instead of in the trunk since there is not a lot of room. I have heard that changing the audio system in the Z has been very difficult so I was trying to see what some of your problems have been or what some success stories have been.

If anyone has any pics of what they did, I would love to see them. Thanks!