Hey there, follow tuga! 👍
You seem to know your way around photomode, using the focus and shutter speed in a good way.
Now, I don't know if you're planning to post only unedited shots, but if you are, try not to shoot cars on phototravel (sunny locations are ok, but still don't look great on monitors), or shooting cars while they're in the shade.
Because GT4 pics always look better and brighter on TV than on monitors. they also lose contrast when viewed outside the TV.
If you plan on edit them (even if it's only cropping the watermark and resizing them), drop me a PM and I'll give you some advices.
On the shots themselves, try not to have the car place too centered on the frame, it looks much better like you have the Civic on Grand Canyon.
That's my favorite, along with the 4th shot.