The stock HK system is so muddy, and lacks any bass response. It's terrible. I really wish I didn't pay the money for the upgrade.

I want stock looks so I plan to keep the mini head unit but I found integral audio:

http://www.integralaudio.com/index.p...coupe-r58.html

I've found lots of threads about the IA package on the R56, but since the R58 is smaller and has less speakers I would like to hear experiences with this set up. It's quite expensive just to take a shot in the dark. Thanks in advance.

 

I would shoot the Integral Audio guy a PM, he's on here a lot. User ID = Integral Audio

 

Yes, I purchased the whole setup (subwoofer as well) and had it installed in my coupe.
I too had my doubts re: cost/benefit, but researched the comments quite extensively. I believe on their website they have a forum, also in this forum there are discussions as well.
Integral Audio worked with my installer throughout and also promptly sent out a part that was missing in the original order. Items were packaged professionally and shipped fast. Customer service was top notch and personalized.
The biggest difference I hear is obviously in the subwoofer. There is also a much greater ability to fine tune the highs and sound quality by using the fade to the supplied higher quality speakers.
It was worth the hefty price tag in my opinion.

 

I have the full system in my R59. Yes it is worth it.