Problem is it looks good both ways. You just need to decide whether or not you want your van to look like 20,000 others in town, or if you want to stand out. Looks like you have a pretty nice paint job, if you didn't I'd say do it for sure. Not sure about the chrome grille painted black. I'd say black wheels, bumper and cladding but leave the grille chrome. Then slap on a set of black reflector headlights and turn signals.
I painted my bumper with "bumper paint" from Duplicolor and it looked awesome until it began to flake off. Somehow I doubt a "professional" paint job would stick without flaking after a while either. You might just take an awesome looking van and make it look like crap!
Well, that was helpful.

Some of my mods live only on my hard drive, like those in my sig. Good luck! Your van looks great as it is.