Either I'm just lucky or I have the knack, but I just don't find those clips to be tricky at all. Just remember which way round they go, and they clip on and off easy. Press down and in on one side to remove - you might need something like a flat screwdriver, but usually can be done by hand. Put one side under the rim when replacing, then press in the other side - down and in.
Perhaps I should set up a clip removal/replacement service for all you scaredy boys
I have the 7" Tribar on my G5 - looks fantastic and gives way more light than the stock. Very easy to fit, straight swap. The only tricky part I found was getting the new unit to stay centred in the original rim. I cut some little strips of 3mm hard rubber which I'd had lying around the place, and put them at 4 or 5 points between the new unit and the old rim. This held things centred while I put the clips in.
There is no hole in the new unit for the parking light, so you'll have to remove the bulb, tape it over and just tuck it to one side.
A couple of folk told me it would be a bit of a squeeze to cram the new unit in, but it's actually the same size as the stock unit and fits in easy, and the electrics just plug straight in the same way.
Mine is the Adjure unit, from UK supplier but same brand as NField Gear supply.
The instruction sheet (scabby photocopy) mentions an "extended bezel trim ring" which is available if there is a gap between the lamp and the rim, but this doesn't apply to the G5 - just the centreing thing as I mentioned. I'm assuming the C5 has the same nacelle...?