That one is a slight variation of mine that I was talking about. My spoiler and fog lights are different
What do you mean the edge between two parts? 
Looks pretty good for a first car/blend/lighting&scene/all that stuff 
congratulations! I’d say that the background and car are fine in the render, and apart from the headlights which you mentioned the only thing you might want to remember for next time or a re-render,would be the fix the tires a bit so it doesn’t look like it is floating. oh, and the rims looks a bit simple compared to the rest of the car.
Yeah I couldn’t find any good pictures of the tires… I was having difficulty finding pictures since this is such an obscure car! Thank you though
A bit late now, but this site has a lot of ref images: http://www.netcarshow.com/porsche/2014-911_gt3/
A solution for the problem, that the background color will be reflected in some areas of the car:
You can uncheck the ray visibility of the world or of any objects for glossy materials (look in the world, resp. object settings).
Btw, 3.5 hours are not that much. It took me 13,5 hours for each picture of my Dino 246GT (rendering + composting for A3 and 300dpi).
Attachments
