I'm looking to add a subwoofer amp to my 2001 Coupe with Bose. From what I've read on this forum, including several very informative posts by you, at the head unit I can tap:

1) low-level, pre-amp, left and right signals
2) remote amp turn-on

If that's true, then why would I need this :

Pac Audio AOEM-VET1

Some other members, including professional installers, say the Pac Audio unit is required, but from the info I garnered from one of your posts, I should be able to simply splice into the pre-amp signals near the connector behind the head unit, and connect them directly to my sub amp's low-level inputs. But, then again, the Pac Audio unit shows some kind of box, as if it's got some converter stuff, or a transformer in it. Is that a gimmick to try and scare people into buying their product instead of simply tapping the wires in the factory harness, or am I missing something here?

Thanks,
Kelvin