[TSi+WRX]

^ That's very feasible for sourcing power - but it unfortunately will not allow remote muting using the actual SmartCord.

In order to use the SmartCord for that feature, he'll need to run its wire, somehow, down to the dash/console area.

And in this instance, trailtow101, you'll need to consult the vehicle-specific enthusiast Forum/community, to find out exactly how the curtain deploys, and what can be done to route your wiring safely.

For my Legacy, for example, many had wanted to mount ancillary monitoring gauges on the A-pillar. Concerns, however, were raised due to the curtain airbag that deploys, in-part, from that location (which is a part of the reason you will not find aftermarket pillar-mount gauge-pods for the BL/BP-chassis Subaru Legacy). It wasn't until a member was kind enough to post his curtain airbag deployment pictures that it was seen that mounting to the LOWER half of the pillar was indeed safe, and that wiring hidden in the junction between the A-pillar and the windshield was also exempt from such deployment concerns.

This is why you need to consult your specific-vehicle community.