MarkinHanover here with a couple of cars I am working on to improve the audio on and looking forward to hearing your advice and knowledge. The last car I modded the audio on was a 2006 Pontiac Solstice. Right now I have 2015 Camaro LT1 convertible w/Nav that I'm in the process of changing the speakers on. Changed the rear side speakers to these Infinity Reference REF-3032cfxthat went in pretty easy and sound great. The door woofer speakers and tweeters (Hertz K 170) that came with smaller tweeters than stock I decided to up the tweeters to 1" Alpines (Alpine SPR-10TW). I don't think I want to "mod" the tweeter mounts on top of the doors so I'll have to find a surface mount location on the flat parts of upper doors.
My other audio project will be to look into my Mazda 6 Grand Touring w/ Bose driver's side woofer which are now notorious for getting water damaged and tearing.

Hertz K 170