Don't. Most probably it'll be a waste of time. I have read about the idea multiple times, but sofar I've not heard from anybody: Wow, what an improvement this is! Also realise that the K3/4 models were already very lean indeed (EPA) and were - as a matter of fact - often criticised for this.
I am wondering if the earlier CB500/CB550 models had these pushed in.
Yes they had.