Yeah there's definitely a good amount of wires involved, especially if you want to get good sound.
Ok, from first glance, it looks like you're missing part of the reason for doing a Car PC.
So why not get a XM Direct unit or XM PCR, copy your music files to the PC's hard drive, and eliminate the Inno, the Ipod, the Soundgate Aux3 and all those wires in-between, altogether?
Otherwise, your system looks like it's going to sound great.
I dont think Mic in is stereo.... please correct me if im wrong. Line in is stereo, and you could always use a splitter so you can connect them all together.... just have to make sure they all dont run at the same time, otherwise it wont sound to good hearing all of them together....
Nirwana Project, the Android/Win 7 hybrid system!
1X Ainol Novo Flame Tab
3x Perixx Touchpads
3x 7 inch Screens
1X 7 inch motorized Screen
1x Win 7 PC