Mike I'm really glad you liked your JL C2/Fountek upgrade!

With 12-13 year old door panels and such I would expect to want to do some sound deadening, even without upgrading my speakers, just over the years and taking the door panels off a few times I notice the occasional rattle on mine. I am probably going to get some GTMat like Prop and either do the inside of the door panels or put it on some areas of the door skin when I do my door speakers.

Also take a look at the area where the door panel meets the sail panel of the tweeter - I had a bit of a rattle there and stuck a piece of sticky felt on the sail panel in that spot before I put my door panel back on last time and it actually helped a lot -

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2018 Ram 2500 6.7L Cummins 68RFE
19k miles -Bright White/Black - Big Horn Sport - Crew Cab Short Bed
2013 X5 35D (CEO's) - Born on 5/17/2013 -
82k miles - Alpine White/Cinnamon Brown/Premium Pkg, Sport Activity/Premium Pkg and Sound/20" Style 214/Running Boards