If there's one critique I'd make, it'd be to get rid of the HDRI completely. It seems like everyone immediately uses HDRI's to render EVERYTHING, with no regard for lighting techniques, and the fact is, unless you're really careful, HDRI's just make your model look fake.
Pick up "Digital Lighting and Rendering", by Jeremy Birn. It'll steer you in the right direction for lighting techniques. If you look at real car commercials in print, 99% of the time it's a sexy, clean look, with flowing highlights, and no ugly reflections. If you try to mimic that look, the human eye automatically perceives the model as more real. HDRI reflections are often too distracting.
That being said, if you must use an HDRI, try to make it in context. Check out this link for examples of excelent HDRI use. Most of these pictures are modeled in Maya, and rendered with the PURE hardware card.