I'd go without, it looks rather oversized. Perhaps experiment with some black paint on the foam to give the impression of mesh? I would try something like thinly painting some black onto a flat, smooth surface and soflty setting the foam on the paint so just the surface pics up the paint... it might look like mesh? Worth a shot, I guess, you've got a hunk of it leftover.
You're building a replica of your buddy's car, right? Did you go to his garage and say, "Hey man, could you tip your car up on a side so I can do the chassis details right?" Man, I love the detail on this thing. But the wheel arches look pretty rough cut, what's with the dichotomy between smooth sleel detail and.. not? Anyway, not to take away from it... it's awesome. I love this build, and am rather impatient to see updates. Keep it up! and hurry up!! (But don't rush it... eh, do whatever you want....)