Until recently, Mercedes have never had very narrow gaps but they have always been perfectly aligned. I've never been concerned about it even if some pundits seem to think it's a problem. Those same guys used to complain about the hard seats, big steering wheels, lack of cup holders, yada, yada, yada.

As for anything getting in the engine compartment, the W124 has an encapsulation panel on the bottom which keeps everything out. On the top, there are channels where the edges of the hood meets the fender lines. Nothing will get in there either.

Rest assured that the finest automotive engineers in the world have designed the W124. These are cars that would be perfect if only the U.S. Government didn't have stupid regulations about lights, etc.