The the biggest problem folks experience with high efficiency speakers is typically from the noise floor levels of the electronics, especially noise from tubes, and specially noise from tube pre-amps and tube sources. Thats not to say you won't hear more RFI or other line noise, but if you don't have any now thats a good sign. Especially if there is not much difference between your present speakers and the DB99's.
PS I'm not a DB99 owner.
PS I'm not a DB99 owner.