As you said, even tracking it once in a while can lead to rock chips and other things.
If you're set on ACR factory parts, then buying the ACR out right is your best bet.
I went with an 06 first edition and put APR aero, bellangers, motons, stoptechs, OZ wheels, hoosier R6's, racing seat, etc.. and put on about 3000 track miles this year. My front bumper cover is split and really hammered. My hood has chips. There are bug splatter and rubber marks hard into the hood/roof area.
And as you said, the occasional visit to the grass... or.. concrete..
I'd love to rock it out there in an ACR, but for me it made sense to spend less on the chassis when I'd be tracking it pretty hard.
And, someone mentioned resale value. If you're concerned about that, definitely get the ACR. Your coup with all these aftermarket parts will not hold its value like an ACR with factory parts, even though your coupe may have better suspension, etc... You could always put the suspension on the coupe back to stock, however the holes from the wing/canards won't cover up so easily.
Oh, also, personal preference but I prefer the APR wing (and their new splitter) over the ACR's. I feel the ACR is just a little too wide that it looks a little goofy, although I'd imagine it does perform a little better. I'm sure the ACR's wing is also much higher quality than the hollow APR's. The redesigned splitter in the APR kit also appears to cover more front area than the ACR's (from what I've seen). The ACR's piece is MUCH more thick though, its a really solid piece where as the APR's is honeycomb fiberglass. The way the ACR's splitter is mounted a bit nicer too.
Hope this helps, and hope to see you out on the track some time!