I finally bit the bullet. After 2 years and 24K miles of daily commuting, I upgraded the front speakers and amplification on my car. I have 2007 Cayman S with the sound package plus and PCM. I wanted to keep the PCM interface, but get better sound.
The system is fed off the outputs to the front speakers. The mid ranges and bass for the front doors are tapped at the ASK amplifier in the front trunk. The tweeters have to be tapped in the dash. All three of these signals are combined using a JL Audio Clean Sweep SSI (signal summing interface(BTW, my installer used a RTA to make sure he had the complete signal)) this signal is then fed into a JL: Audio CL441 dsp, which is an oem interface module. From there the signal is fed into in Alpine MRV-F400 (an old 4/3/2 amp I had laying around) in front trunk, and out to brand new Focal 165KR's. Yes...just a two ways. I did not want to deal with the issues of sound reflection off the front glass...and it lowered costs and simplified the install. The midbass is in the lower part of the door and the tweeter is in the upper part where the mid range.
So how does it sound? It is a huge improvement over stock....it plays both significantly cleaner and louder than stock. These Focals are phenomenal speakers. It has much better bass as well. I have not listened to it directly versus the Bose, but I did not order the Bose because I was not impressed with it at the time. My rear speakers and center speaker remain functional.
The only change I am considering is some sound deadening to quiet the car (I know it is sacrilege to add weight...so please don't yell).
Total price $1700 installed.
Sorry there are no pictures...there is just not much to see....
Another interesting note. My installer said that the speakers were far more capable than he would have expected...the amplification and tuning were really sup optimal.