Because the Smart is ISO to start with, I bought the mating connector and soldered the bare ends onto speaker cable coming from the amp, I also had to wire a capacitor in circuit to roll the bass off the tweeters (the smart headunit is bi-amped with active crossovers). I suppose you could just lop the ISO plug off yours as it's only the adaptor, it's not like you're chopping into the factory loom.

As for the remote wire, assuming it's not powering something like an aerial amplifier (or power aerial) then you can just chop it on the adaptor part of the loom and wire it to your amp. To be on the safe side you could just tap a wire off it and use that.