Well, if you're keeping the truck as is, and improving performance on the E-Metro, why not keep the Mercedes to just play with? If you don't require it for travel, you can do all sorts of Unholy Mods to the Mercedes chassis, suspension etc...in the name of SCIENCE!
Seriously though, why not? Take out extraneous weight, grab a friend with a cutting torch for any serious work, plot out Bodymods in Coroplast and execute in Fiberglass-heck, even I can do fiberglass panels and i'm an idiot...
All this will(naturally) take a little money and a lot of labor, but if you don't need the Mercedes you can take your own sweet time with it. I mean, you BUILT YOUR OWN EV! Ecomodding and tightening a Mercedes should be sweet, sweet cake...if nothing else, trim and shorten the frame and make a Kit-built out of it.
Mmm...cake. S'cuse me, I need to make a snack run...