I think if you go with the simple duckbill routed properly you'd get the same results. The Krankvent is just a glorified version with some "shine" to it I think. The Duckbill works just fine from what I've read, the only reason I went for the Krankvent was because of the huge discount. It works, but it's nothing ground breaking or special. Forgetting cost, I'd just go with what works.
If you start going over 5500 rpm, you'll definitely notice the difference.The KrankVent is better.
Wow this thing is loud. I currently have it routed up under the seat then down towards the airbox. Any suggestions on how to route this thing?