it lessens SQ. Short explanation is the way bass expands and reverberates in the cabin is not the same as the trunk.
As for fitment, its not hard getting everything to fit well, it just takes careful measurements and cutting. The last box I built I didn't pay attention to where I measured and when it came time to test fit, it was off by about .5". Had to take it all apart and rebuild it, after cutting off 1/4 from each end. After that, it fit like a glove. (see post with pics of komodo9s install).
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>