mounting speakers in doors

So I've been struggling with speaker bracket issues on all 4 doors of my 2013 Lexus GS350. For a while I had annoying rattles and buzzes coming from around the speaker area of all the doors especially with midbass. I ended up applying foam on every clip, and adding cloth tape to secure them in...

I'm planning to mount a pair of 6,5" component speakers in my 2003 VW Caravelle's doors. I have been searching around the internet without finding anything close to this topic. Doors have these grills installed, behind them is just a sealed empty box. I have been looking at two ways at fitting...