Well till now for some few hundreds of kms driven so far with this new air filters, few things i observed are,
low speed low ratio those vibrations are not felt and car can take over without changing the gears.
Overall there is a change in the way car pickups as it used to before, seems easy and lighter now then old stocks
On complete slow down instead of knocking down and engine stops it gives time to slot up, i mean tried on second gear with complete foot off and it was still moving rather then knocks and shut, i hope am able to make you understand this difference buddy.
Well as far as keeping it as OEM product the main reason is the costing and overall stocks so why would any car company like to do that, every single penny saved is earned buddy, and does every car owner really cares to see this difference as most of the cars sold runs out complete life cycle from stock filters replacements right.