I had to get a different exhaust because of my Syria plans (the leaded fuel thing). The OTR 2-1 was the only one I could find where I could place the catalyser back when using non-leaded fuel. Then you start thinking, if I've spent this much money on a bleeding exhaust anyway, might as well get some filters too. And the PCIII to sort out the fueling. etc. etc.
I bought the tank from Paul666, credits for the idea go to him. There's no tubes or anyhting, I just remove it and fill the main tank. Now I won't be needing it for a while, I'm thinkink of putting a plastic tube in it's place, in which I'll be able to store my tripod.