Painting /Powder coating there will always be arguments but my 2cents worth is that the people that bag powder coating are not up to date with current technology the improvments in coating tech over the last 10-15yrs is astounding and i know this because i work in the industry i teach auto painting TAFE and have a business that does blasting/painting & powder coating as well as qualified painting inspector.The problem of corosion creep under a coating is not only under powder coating ALL paint is pourous to an extent how well a coating is looked after is the most important part having said that a coating that is applied badly or not used as it was designed is where most problems start so choose your aplicator carefully,you were right KTM do powder coat there frames as do every other manufacturer not just bikes almost every thing that is made on a production line is powder coated you would be astounded at some of the tech that is comming out,paint cured with UV light,self repairing coatings etc.So the short of it is paint it if you wan't just use a good aplicator that uses good quality materials and the same for powder coaters if they don,t seem be up to date with new gear maybe try someone else.Just my 2cents