It gets complicated designing a proper airbox [ Helmholtz resonator ] as the Rocket would require a large unit and then you want to make it pleasing cosmetically SO the free flowing air cleaners are the popular choice
Stuff popular, Art - Easy is for others. If I'd wanted easy I'd have stuck with triple K&N's - (actually no I'd have stuck with the single one under the tank) rather than offer my assistance to Battersea when he had an original idea. R+D is what keeps me sane.
As for cosmetics - Aesthetics are very personal. I personally for example do not like how the 4040 or 1770's look. This does not mean I don't appreciate the benefits.
Personally (as an example) I like the look of Bob C's RAM induction system - but not at the expense of filtration. imo it's a crying shame it's not been capitalised on.
I know it's complicated & requires a huge amount of MIPS (Computer jargon: millions of instructions per second) and masses of data to calculate correctly. - but I also know they work.
I've a mate in Switzerland who works on airflow and ducting on F1 racing cars where cost is a minimal factor. But he has no interest in looking at R3's - I quote him
"Chris, I have better things to do with my sparse free time - anyway that's what my wife says".
One could for example consider a scoop, where many have sump spoilers, feeding a decent chamber from below and behind - coming up under the left knee. This idea was proposed by an aeronautics engineer.
I'm also a big fan of the 80:20 rule of engineering. 80% of what's possible for 20% of the cost possible. So I could accept less than perfect dimensions if I got reasonable return in gain.
This said - personally I doubt I'd take the plenum route as I'm sure price/performance benefit (FOR ME) would be unjustifiable. Mainly I don't need more performance than I have. It does not mean however I'm adverse to furthering my knowledge.
