You can download workshop cars (more than 250 different ones) for free to get more variety. You have much more parking space to buy for storing you car collection. You have even a battery charger so you would never buy a battery new again (except it is missing right from the start). In CMS2018 tyre and rim are different parts now and you can change their witdh and size. The test path looks a lot more professional and seems to be part of a racing track. Testing tools are mainly the same as in CMS2015 - but you now get additionally a tester for the tyres and a voltmeter. If you now in 2018 had to change body parts, you have to go to the paint booth to paint them, there will not be automatically painted in the car's former colour scheme if assembled.
If you have changed the visual decoration of your garage, the reflections in 2015 still were from the standard garage. The shadows are not static anymore like in CMS2015, where the shadow of the car on the lifter always stays the same, if there was an engine in the engine bay or not, if the lifter was up or getting down. The biggest changes are the visuals, as you now have dynamic lights and reflections.
