Foam on stock air filters?

[Mad Max 93 RT10]

Ok so I'll ask a stupid question here seeing how I hate the search engine. I had the original gen 1 air box front half on my car until two days ago. I had already installed the gen II rear half on it (reverb canister delete) and was waiting to put the gen II hood on to put the front half on. I noticed on the orginal air filters there used to be a foam element attached to the filters but was removed. When I installed the front half of the airbox I also had another set of fitlers that came with it and they looked better but had the foam still attached. I took it for a drive and instantly noticed a lack of throttle responce and less power. When I got to my destination I popped the hood and ripped the foam off the air filters and drove home. The power and throttle responce was back again! I couldn't believe the difference from the foam being removed! Why is it there and is there a danger of not using it? I'm changing my intake completely once I find one that I like.

[RTED]

Stock air filter elements are ridiculously restrictive. Make the investment in K&N's and maintain as instructed with the detergent and oil kits that K&N makes. Life time investment, more power, sound throttle response. Some claim increase of 10hp + gains with smooth tubes. Easiest power adder for the viper.