Holy F Shit! I've been trying to render some cars with Blender... But hell this is so hard. My Favourite car is Pontiac Firebird '73, I want so bad to see that car in such an amazing render like yours.
it's great. really great but it seems a tad souless in it's final outcome. i think it's very impessive but it doesn't really excite me. i can't think of a better way to say it than to say it's like a show home that doesn't look lived in. it reminds me of the will smith film "I Am Legend".
after that negative comment i'd like to say i love your work and i really appreciate the detail and care you take creating it. like the attachments of the bumpers in the arches and the hardness of the light. keep up the good work!