After blowing my stock HK door woofer and replacing with 4ohm coax and not really liking the sound, farty bass and pops. I picked up some JBL components and just used the woofers.
The sound is amazing, it improved the overall sound of the system.
Im a musician and an audiophile on the cheap lol. I can enjoy to growl of the bass guitar is certain songs Pretty much I have clarity

I used some aluminum tape about 6" wider from Home Depot for sound deadening.

Just thought I would share since there are people out there that think you need to spend a grand or more for the vehicle specific kits and that just upgrading the speakers wont do a thing. They are wrong. These are 2ohm and cost 79 bucks on sale.

Could still benefit with a sub

 

Doubt the tape had any effect on sound deadening. I Dynomatted the hell out of my car, doors, floor, panel, and some of the roof and hatch. I've also listened to other's MINIs with just speaker upgrades and just wasn't impressed at all. Even some with speaker upgrades and subwoofer installs just didn't sound good at all, and those weren't cheap. You still have the issue of the different frequencies not going where they should. I bit the bullet and put in the full Integral Audio system, Soundstage and hidden subwoofer and their own cross-overs and there is no comparison. In fact, I purchased the last subwoofer they had. This system rocks but I understand if someone doesn't want to spend that kind of money on a system. Just don't tell me swapping out speakers magically makes the system amazing. It might be better than stock but that's about it. In my opinion, the IA system's sound is amazing but that is what I expected due to the cost. To each, his own and enjoy! That's what it's all about.

 

The tape I used wasn't really for sound deadening but more possible rattles between the door , the plastic and the speaker.

The difference between the stock door woofer and the 6.5 component woofers I installed is night and day. The mid and tweets actually do sound a bit better, but thats also dependent on the source of the audio and the audio track itself.

For people that dont feel like shelling the cash on the IA or Bav stuff, this is viable solution.

As far as different hz going where they shouldn't These handle was they are designed for just like the factory crappy HK paper woofer just way better

 

I demoed the IA system in a 2nd gen car in anticipation of it being available for F56. I was underwhelmed.