I agree with Dan, KB still hasn't worked out all the oil spray problems. You might get a good one, you might not. I've been happy with my Whipple (after the initial problem I had). Very similar performance between both blowers, it's really just a matter of personal preference. I personally wouldn't get the KB until I knew they fixed the oil problem. Maybe SVTDubs will chime in on his 2.4 KB. He's the only person I personally know that owns one and I know at one point he had oil spray issues.
I also think the Customer Service for both companies leaves alot to be desired (unless you're one of their "high profile" customers). My Whipple Customer Service experience WAS NOT satisfactory as was my experience with KB back when I was getting parts from them for my GN. More recently though, I did get good service (and a good product) from KB when I purchased my BAP.
I would look on ModFords for some additional Whipple/KB info/drama before making your decision.