The Yakima system works like this...
The cargo (bikes, skis, etc) are supported by the crossbars.
If you don't have compatible factory crossbars, you buy Yakima crossbars, and Q-towers that support the crossbars a few inches above the roof.
There clips that reach around the edge of the roof and pick up the doorjamb. Latches on the towers pull them up tight.
Works great and is easier to install/remove than you might think. I can install mine in ~5 minutes and remove it in ~3 minutes.
So for your car, you'll need the bike rack, the crossbars, the Q-towers and the clips.
The bad news is this stuff is expensive -- ~$500 nowadays.
Moving a single rack system (Q-towers, crossbars etc) is not feasible since different clip models are required to fit all the different door jamb shapes. And changing the clips is not trivial; probably more time than you would be willing to expend very often.
Make sense?
I've had mine for 10+ years and it is bulletproof. I like the fork-mounted bike racks; others like some of the other varieties. It's all good!
-Tom in SoCal