I like the cars' thing, specially that you mixed the pick-up's mouth and (I honestly don't remember where those eyes come from) those menacing eyes in a kick-ass cavallino. I can spot somethings i'd tweak a bit: the right end of the front has the same reflections as the original front end, yet it has much more different shapes that don't reflect in the same way. The wheels should have a bit deeper shadow in the parts that are just down the wheel arches, specially in the case of the tires, and the grey parts I'd put them with a carbon texture (This is something personal, i'm experimenting with carbon now, they look nice in that grey coat nev'theless) yet, anyhow I think they lack a bit of contrast.
I hope this serves, i'm just learning as you're

Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere.
Colin Chapman.