I am considering buying one of Neumann's live vocal mic offerings, and am curious as to the difference between the KMS 105 and the KMS 150. What is the determining factor in the price difference? (Manufacturing, element, electronics, etc.)

The vocalist who would use the mic is female soprano, with a quite airy voice, and I want to capture the body of her vocal without sacrificing clarity and air/space, all the while getting LOTS of gain. Is one of these mics suitable?

Any information would be greatly appreciated.