The only input I have is the following, although it is still an unresolved issue.
My girlfriend had her 2010 Forester at Dyno-Comp for a coil-over install. Signature Audio is next door, so so she paid them a visit about improving her stock stereo (SW controls + XM existing, spekaers aleady upgraded.) she engaged them to install and AudioControl LC6i, amp and a Focal powered subwoofer under the front passenger seat.
Upon pickup of the car, it sounds good, and all works well. One minor glitch - the air bag light is on. Signature says take it to the dealer, as these things are sometimes sensitive and the dealer can clear the error. If there is a charge, Signature will pay it.
Diagnostics at the Subie store lead to discovery of a subwoofer mounting screw THROUGH the under-seat airbag wiring harness. OK, no big deal - although pretty amateurish. BUT, the Subaru approved fix is a new harness (understandably) for about $2000 installed!
Signature has said they will make good (offering a gift cert and a solder/shrink-tubing repair) but needs to see the car. So, the car will go up there next week. I haven't seen the issue myself, so I can't explain any more about it now.
So, my point is that they seem to be good folks, but made a big mistake here...
PM me later for an update, if you want.