I held off on responding to this post as I am no audio expert, but there haven’t been too many replies so here is my two cents of experience with Monsoon vs. Aftermarket.
I am kind of in a unique position to offer advice, as I have both an ‘all aftermarket system’ in my Impala and retain some major parts of my stock Monsoon system in my Camaro.
Like Wade said, Monsoon systems are good for stock stereo systems and a good base to build from. Monsoon studies the interior space of a manufacturer’s car and locates/pre-wires speakers in strategic places to provide good fill. I find their amp’s Dynamic Distortion Limiting partnership with the stock Monsoon speakers to be excellent. I will say my local stereo shop has very few positive comments about Monsoon systems (profit motivated attitude?), though they do not mind taking my money for additional components to add to mine. I looked around Monsoon’s site http://www.monsoonpower.com/index_auto.htm
(click on "models" then "chevrolet") and did not find a place to order any of their automotive systems, though you could probably go pull components inexpensively at a wrecking yard. My guess would be the eight channel (or more) amp and the speakers it powers would be the best parts to extract. These are the parts of my original Monsoon system I still utilize. Then you would just need to find locations to mount all those speakers in your 9C1.
My experience with Monsoon:
The Monsoon head unit I pulled out of my Camaro is physically identical to the stock head unit I pulled out of my Impala (other than saying ‘Monsoon’ on it/CD to tape player), though I cannot say about how it’s constructed on the inside. Email me if you want some pictures of the two stock head units next to each.
The Camaro has less cabin space to fill with sound than my Impala and it has one more speaker (9 to 8). The Impala is running one more sub, but they are all free-airs compared to the two stock subs and the one boxed sub (stealth) in the Camaro. The Camaro does have the treble advantage with separate tweeters in the doors. Sometimes my ‘survival instincts’ compel me to adjust the treble down (-1) before my skull explodes.
The Camaro sound is incredibly crystal clear (DDL) and will overpower the occupants at a much lower volume level (50-60%) than the Impala (65-75%) with identical head units and different amps.
What is amazing is that eight of the nine speakers in my Camaro are stock Monsoon, all powered by the stock Monsoon amp and if I was going to enter a sound off competition tomorrow, I would take the Camaro over the Impala!
If you look at the expense of putting in eight aftermarket speakers in the Impala, two aftermarket amps to drive them all compared to just adding one aftermarket amp and sub to the Camaro’s stock Monsoon system, and the Camaro still sounds better to the owner of both, the Monsoon is one awesome platform to build from!
I can’t help you with the steering wheel remotes/wiring part of your question. I’ll stick with my remote controls.
Sorry for the lengthy reply. More system details in the link below.