Tint - Not my bag, but will look sharp either way
New exhaust - absolutely, but I have no idea who's got the good kits... Just don't make it sound like a redneck's mud truck, as is so common...
C-pillar louvers - Tacky, tack-on, J.C. Whitney looking trash... If you do that, you may as well have "C'YA" put in big letters in your rear window tint, "2-fast-4-U" in the front tint strip, get one of those chrome chain-link license plate frames, and order up ten or twenty more cobra snakes and Shelby emblems to plaster over every square inch of the car... (can you tell that I don't think much of tack-on busy styling stuff??
)
New wheels? Only if you're talking about going back with stock diameter. If you're planning on increasing diameter, you:
1. Foul up the dynamics and ride of the car
2. Fall into that poser catagory, like all the goofballs out there running dubs on Escalades. It's a fad, and it's on the downslope (thank goodness).
If you're thinking about going with a rim that will make the car look more serious, then I can give you a thumbs-up on that. I think the stock wheels are fairly attractive though.
With modifications, especially cosmetic, it's so easy to accomplish the opposite of your goal. Taking a classy looking car, spending a bunch of additional dough, and winding up cheapening the look of it with overwrought cartoonish faddish "stuff".
Keep it clean and purposeful. A guy wearing a flashy outfit with 5 pounds of gold on his neck and wrists, and a diamond rolex, just looks foolish and vain and desperate. Same goes for cars..
Love your color choices though, you've got a great start...
So those are my opinions. You asked!!!