I've been talking about it for a while, but I finally put some numbers together. My trunk is very small because it shares space with the fuel tank. Dumb, I know. I can't port through the ski hole, I have to port through the OEM 'woofer' 6.5" in the rear deck. Drivers of choice are a pair DD 2510's.
Numbers are as follows:
These are pretty much maximum. Doesn't yield a whole lot of space, I know. The 2510's have a depth of 6.5"... I prefer a dual chamber enclosure, so I can have a window so I can see the front of the subs.