It does fit in the Car Dock with the Shell installed.

When putting it in the dock flip up the tab on the top. Then, place the phone in and onto the USB plug. After that take and fold down the tab on the top to lock it in place. It's a very tight fit but it does work.

If you try to put it in the dock without flipping up the locking arm on top it won't go in right.

 

The insert is there for if you do not have a case/shell on your phone.

 

Actually, the insert is for people who don't have an extended battery.

@UncleMike:

You have to take that insert out to use with the Shell/Extended Battery. Once removed flip the little arm on top up. Then, slide the phone onto the USB connector. Then push the top of the phone towards the dock and flip the arm down to hold the phone in place.

Pictures:

Step 1:
Mount dock on windshield and flip up the little lever on top.




Step 2:
Slide in from the top at an angle and push onto the MicroUSB Connector at the bottom of the dock.




Step 3:
Push on the top of the phone and flip down the locking arm.





Notes:
If you don't push in the top you end up with the arm sitting on top of the phone and not holding it in the dock.



Also, with the shell installed you can't use the power button on the side of the dock to turn the phone on and off. It doesn't line up.

So while the phone will fit with the shell installed it's not perfect and a little forced and the buttons don't line up properly. Just make sure the screen is on before inserting into the dock.

 

FYI. If the retaining clip gets in the way a lot, its easily removable. Use a small flat heat to remove the rubber covers on each side of the clip.. Use an allan wrench to unscrew the bolt while holding a finger over the side with the phillips head (its spring loaded). Remove the bolt. nut and spring. Then on the bolt side, put the white plastic bearing in and it will pop right off.

I hate these clips as they really just help reduce vibration but make it more cumbersome to remove the phone quickly. Hence, I removed them on my DX car docks as well. There just isn't enough vibration occurring in my cars to make it worth keeping.

 

Without the arm the Bionic wouldn't stay still while docked with the Shell on. The shell makes it sit forward a little and it would just bounce around unless held in place.

 

I see. I run with no case on my phones. I would still think the lip on the right side of the dock would hold it in, but I don't have a case to check with.