So, to back up what you have put here, definitely go with the speaker replacement and if you want you can upgrade by steps to a true tuned aftermarket system and get improvements all the way.
Yeah, for me, the speaker replacement was really just a "pre-req" before I started adding amps/processors. There is nothing like great-sounding, powerful car audio! And I disagree with
- I think that sound quality still plays a very important part - even when the windows are open and the radio is really loud. A really good-sounding system is just sooooo nice - *especially* at loud volumes! :-)
The system I put in the Charger was about $800 total when I was done and used the infinity Reference speakers recommended here with an added 10" sealed sub, JBL 3-channel and 4-channel Amps (The GT series, but models are different now), a pair of mini-DSP sound processors (but they make a better single unit specifically for cars now), and a Pac Audio LOC, but for 2015-up cars that unit would be different and expensive, so the Audio Control LC7i might be better. The Infinity's sound great and I can say that the 506W Alpine in my new Scat Pack doesn't sound nearly as good as that system. Once it is tuned it sounds pretty awesome. I used the open source REW software from the Home Theater Shack forum, and a calibrated mic on my laptop. It was a lot of fun tuning the system and the options are endless. This is the curve I ended up with.
Very nice setup!! I'll be honest, while I love good audio (home audio and car audio), my DIY car audio experience is pretty limited. Typically, I just replace the stock head-unit, the stock speakers and maybe add an inexpensive, low-wattage 4-channel amp and I'm happy (I was really impressed with the Kicker KEY180.4 with it's auto-tuning capabilities). However, being that I can't just replace the head-unit in the 2018 Challenger like I could with older cars, it makes upgrading a little more "complex". I'm pretty comfortable with audio in general and know enough that I really want to get into the full processor setup that I have complete control over and can tune myself - and take things to the next level in my Challenger. The Rockford Fosgate DSR1 and T-harness combination looks like the perfect setup for the Challenger. It's a great LOC and DSP all-in-one and actually seems pretty damn awesome for the ~$250 price tag! I really like how you can adjust everything from an Android or iPhone device instead of needing a Windows laptop for tuning. However, I will need to get a good RTA setup to tune it properly myself, which is all new to me. I'm also very "green" in the "clean install" area when it comes to processors, multiple amps, etc. Was considering paying a shop to do it, but that would cost a small fortune and I kind of want to learn a little more about the tuning aspect. I just hope I can make a nice clean setup like you have going on! :-)
I'll attest that I ran into the exact same mounting issues with these speakers in the door and rear deck positions.
Thank you! I'm so glad to hear that it wasn't just me!! I mean for the rear deck speaker issue - the speaker, the adapter plate and the screws all come with the Infinity speakers - it makes no sense that they include screws that are too damn long to correctly mount the speaker to their own adapter plate!!!! On the other hand, the fact that the Infinity 6"x9" speaker hits into the stock door mounting adapter - I can completely understand that - and am used to dealing with stuff like that when replaceing stock speakers with aftermarket speakers, but the whole "screws are too long" issue with the 6.5" rear-deck speakers was annoying - that should not happen when all of the parts are coming from the speaker manufacturer, in the same box. :-) I also wasn't happy when I found that Crutchfield is supplying the wrong speaker wire adapters - again, that is something that they "pride" themselves on - they should get it right. I seriously wonder how many people are driving around with the speaker polarity reversed becuase of Crutchfield including the wrong wiring adapters. That being said, I will definitely let them know (backed with "evidence") so that they hopefully correct the issue. Mistakes happen - it's how people handle the mistakes that really matters. :-)