48" X 44" is about the dimension of the W124 TE Boot. some minor encroachment by a wheel well.

I have 3 kids, and refer to my TE as the "Anti-minivan". My car didn't come with the third seat, but I retrofitted it with the OE setup. What a Godsend. When my 4 & 7 year old daughters are back there, you can barely hear them! And it can carry LOTS of stuff. And if it needs to carry more, remember it's a Mercedes; it can carry 200+ lbs. on the roof. I have a big 'ole Thule box, and can carry 14 cubic feet of flotsam as well as 3-4 bikes. The car's very versatile.

Good luck!

__________________
"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo