Relatively high-priority on my to-do list:
- private messages
- ability to mark vehicles/movie pages to follow, to easily see when there is a new comment made on them

About browsing, indeed this should be improved, it is also planned. Probably through a split view showing one row of thumbnails for movie/model vertically and the vehicle detail on the remaining part of the page.

Note that currently you can use tabbed browsing for a little easier browsing (click with mouse wheel to open in a new tab) to prevent from having to go back each time.