90% of the time I try to be as realistic as possible, so go for as pure of accuracy as possible: with exception made for increasing bokah/lens blur to accent subject.
I am just getting into accenting a single color for photographs: usually live concerts, but some candids in unique setting (like a boxer walking to the ring where I made everything BW except for the color red which matched his gloves and the posts of the ring)
looks like you already have the understanding of not just doing 90 degree photos from from or side, so excellent start. I'd try to explore more variety still of angles, high, low, and straight on (which will still be you kneeling for most cars). Also I've really enjoyed doing some detail pictures like the ones you did of the tail-lights. I bet you could explore that area a bit more.