That is a great call out with the bulk hose that I bought. What I used was specifically intended for high pressure fuel systems. I can't recall exactly where I purchased it, but there are many online places that sell this type of hose in bulk. I think it was about £6 for a meter, so much better than the £27 MB wanted to charge me.

Regarding clamps, I opted for the OEM single-use crimp style. As much as I hate taking them off, I must admit that they are highly effective. The reusable style of these that you opted for I've actually had issues with on my other car (on a coolant line), so I just didn't want to take a chance with the Crossfire. That being said, the Subaru fuel damper I bought came with hoses attached and it had the same reusable style of clamp that you used. I just left them attached and it has been fine so far with no leaks. At any rate, I agree the worm stype clamps are not a good choice for this particular application.