Okay, I'm taking off my Trek shirt and putting on my Indy 500 polo. (Huge IndyCar fan here.)
While I like the basic premise of the comic book concept, I think your posterization technique suffers from too much automation. The two-color process, when you just let the computer take over, doesn't really do that good a job at determining where the shadows should fall. If you're going to stick with two colors ("flesh" and black), then the face should be lit full-on to begin with.
Tony is the prime example here. (My absolute favorite driver, by the way.) If you've ever met Tony in person (I have, four times now, once at Dan Wheldon's funeral), you'll know that you can spot this guy's nose from a mile away. You see his nose peeking out from beneath the pagoda, and you realize, "It's Tony Kanaan!" (That and he's as short as I am, which gives fellows like me a ray of hope.) But the two-color process on this particular Tony photo, where his face was lit mostly from one side, completely obliterates his nose, so when you squint, you don't know whether it's Tony or Bruce Willis.
You chose a great photo. My suggestion is, do it justice by deciding which parts get posterized and how. (My wife and I covered this exact subject in a book we produced for SAMS almost a decade ago:
http://www.alibris.com/booksearch?qwork=7922295) Do a three-color posterization instead, if not four. Go into the photo with the "magnetic selector," which snaps to particular changes of
hue, and separate the sunlit side of Tony's face from the shadow side. Then for the two flesh colors, choose something that's not so pasty beige, at least for Tony. His Brazilian flesh tones are a little yellower. Choose a ruddier color for the center of his forehead and the bridge of his nose. Save the black for the five-o'clock shadow along his right cheek. Then don't be afraid to add a streak of white, right where the sunlight strikes his forehead, and just left of center along the bridge of his nose.
Although your Tony photo has such wonderful contrasts, the E.J. photo you chose was lit with so much ambient light that you lose the distinguishing lines of his face. I'd go in there with a black brush and re-establish his nose, lips, and jawline. Contrast E.J. with Josef and you'll see what needs to be done.
Minor details: I'd either lighten or remove the "winged wheel" logo on the SAFER barrier behind E.J.'s car, because with that shade, it looks like it's coming out of the nose cone. I'd add red to the Yard of Bricks over Tony's shoulder. And I'd add a white streak to the airfoil of the Dollar General car.
It's great that you're doing a page of the IndyCar calendar next year! Maybe Tony will finally win a championship on your month!
DF "An-n-nd Mario-o-o izz Slowin-n-n-ng Do-w-w-w-wn!" Scott