'12 300 seat gap?
 

Has anyone else with a '12 300 noticed the gap between the seat and plastics over the subframe is large in comparison to when they got it? I can get a finger under my seat between the battery and seat bolt area.

Nato.

yes , my 2012 ec 300 is the same way , im not sure why , i have 2 seats and one of them is not as bad as the other , if you stand just right you can see daylight from the other side of the seat 1/2 inch gap , this has me baffled also ......

Plastic subframe?

yes , plastic subframe

I'm thinking the fuel tank swelling of the 12's might be your cause.

Maybe the subframe needs adjusting up a bit?

maybe , ill have to look into the subframe after the holiday madness is over ...