The methods listed will work to different degrees and one person may get the dent out while another using the same method may make it worse. There are too many variables to say any one method will work to your satisfaction. It all depends on how good you want it to look. If you want it to be completely invisible, take it to an auto body shop that does paintless dent removal (PDR). It should be completely undetectable when they are done. I have no idea what they would charge, but I had over 100 dents on my car from a bad hail storm and they got them out completely. I would take the heads and wires off and all of the hardware so they have full access and so nothing gets damaged in the process.
That is a good idea thin shell. I wouldn't have thought of it for this applciation, but I had some dents taken out of a Z3 coupe a few years ago. He got all of them done nicely with the exception of a very small one in the crease of the rear door where it transitioned from the sloped window section to the downward panel. He'd would have had to remove all the interior trim of the door to do it. Because it was such a tight curve he suggested it might not be possible and thought I should leave it as was because the dent was quite small. Looking at a few pictures a moment ago, I can't see the dent, so guess that was a good suggestion on his part.
