I wrote this long comment earlier, but then the computer I was sitting at had a total meltdown so it failed miserably.
I really like this chop, never been much of a fan of the s2000, but with your design really lifts the overall feel of the car. The one thing I still don't like is the roof. I know that's what the S2000 hard-top sort of looks like, but I think Honda made a huge misstake there. I'd like to see a more slick looking roof, with a longer roof-line. If you are up to it, try to stretch the c-pillar so that it connects further down on the back fender. That will give the car a more slick look and I think it could look cool.
If we move over to execution I think it's great for the most part, but there are some toony areas. Unfortunantly I don't know exactly how to fix them. One of these areas is on the roof, where the highlight on the side of the C and A-pillar meets the darker color on top of the roof. One way to make that less toony, I reckon, would be to make the the line there a bit sharper. Use the pen-tool, draw sort of a horizonline between the dark and bright color and then just add a little brush on there. Either dark or bright, whatever you fancy
Regarding the refs in the window, I think Klaus is right, but I don't think those refs are right... Never seen a photo where cloud refs bend that way, they sort of don't follow the windscreen. Should be straighter I think... I could be wrong though
I have been wrong before...
Otherwise just keep at it
Gonna be awesome in any case.
Cheers!