I tour on a Redshift stem. It's great and I can recommend it.

As for Schwalbe Marathon Supreme tires, I've had three of them and none managed to survive until end of life. All died to carcass tears before the rubber wore out. One at 300km, a second at 3000km, the third at a whopping 11000km. They are certainly capable of lasting a long time, but only if you have good luck.