K&N filters and more free flow air filters are good, I run them BUT... one thing you should know is that it will change the air fuel mixture and may affect what the ECU sees. Thus you could actually blow an engine if the mixture becomes too lean.... true story with a subie. I guess it is easy to feel that with an ECU it self adjusts but not so the ECU is built to handle MAF sensors that are match to it.
How it affects a carb engine I would assume needs to be looked at too.
Just saying.