This makes complete sense to me...
...41hp sounded a like a bit much for an air cleaner upgrade, but I prefer the wait and see approach to this stuff.
The non-RHO 1500 derivatives all have closed air boxes. Less restrictive breathing for the engine will add hp.
But the RHO is already a open-airbox, ram-air system. I feel any aftermarket air filter/intake set up might gain 1-5 hp, and could improve the fluid dynamics of the incoming air, but we will never see anything close to the numbers previously mentioned here.