Yes, it sounds fantastic! I had an existing 2-way set of Dynaudio Esotec speakers and we added a Morel Elate midrange (since the matching Dynaudio mid was too large for the A-pillars). The mid bass drivers are in the front door factory locations. All the other speakers in the car were removed. Front/rear/hatch doors and the trunk were all sound dampened.
Using the MoBridge DA1 to convert the fiber-optic network, a clean signal is run into the Alpine processor (the controller is what's in the sunglass holder) and out to a 6 channel McIntosh amplifier for the speakers and a mono Zed amplifier for the 2 12" Stereo Integrity subs. Subs were custom fiberglassed into the spare tire well. Since I had really large amplifiers, we ended up having to raise the trunk floor about 3" to fit everything and built a new floorboard with steel mesh cutouts covered by black carpet.
Factory controls, bluetooth, etc all still function. I was worried that the 115 amp alternator wasn't going to be sufficient to run the ~1300 watts, but haven't experienced any headlight dimming at all.
Now for costs... Disclaimer - I used to be in the industry, so I'm kind of an audio nut and really went all out this time.
Labor: the A-pillars are $650 and trunk $750. Total labor/misc materials are around $2500. Wiring, equipment, sound deadening materials were separate. All in, probably $8000, but I had most of the pieces and wiring from my last car.