Scion would just charge you 300 bucks for what is essentially a 50 dollar, 15 minute do-it-yourself job. As to the low volume issue, with the USASpec adapter I run my iPod at full volume and usually set my HU volume to 45-55. I've gotten into the habit of turning the volume down before hitting AM or FM, but even when I forget, playing the radio at that volume is no biggie. I'd install the line-amp, but I learned from my last car that if you splice ANY wire you void the electrical system warranty.

 

Thanks,
Just ordered it today. Will provide feedback on the installation experience. Now my next problem is my son broke off the driver side view mirror. The bracket that holds the side view mirror looks like a stress point. Need to find the part to replace it