For those that are having trouble with the clips, here is what I suggest as I have also tried and failed and broken clips until I figured out the proper way...
It's a bit awkward but first squeeze/push the connector onto the coil pack like you are putting in on tightly, while doing that pull back on the tab, then while still holding the tab back slide the entire connector off the coil.

Once you get it apart you can see what it really happening. the coil has a small "hook". The tab on the connector has a small notch/hole in it where the "hook" on the coil goes. If there is too much pressure on that point, when you pull back on the tab it will not lift off the hook. Pressing the connector onto the coil releases the pressure.

Anyway, that's my 2 cents on the subject.