Use google, it's nearly as much a debate as engine oil. lol
I think:
- The Scrambler is not a high performance engine, spitting out immense heat. It's just a lean-ish running mildly tuned engine.
- The headers are made from stainless steel, not mild steel, so the odds the immense exhaust flow will eat up the metal from the inside are not that big
- Don't worry about rain, they heat up before you reached the end of the street. It's the extra hot gasses eating the header away from the inside you should be worried about
- Ducati even lists it as an accessory
I guess you'll be fine for looks. Many went before you (check out the bobber scene!).
Cera kote will be better when it comes to gas flow, especially when applied both outside and inside the headers. But stil the header will radiate heat. I had a midpipe cerakoted on my G650XChallenge, but it was still too hot to pretect myself from burning my leg.