i just filled up at a shell that had the signs up saying the gas is now nitrogen enriched, i didnt notice a differect......however, my car is also brand new and the only thing i would think it would do is give a little fuel system clean which i dont need in my new vehicle. we put it in the old vehicle too though and didn't notice a difference either. in summary, i think its just marketing trying to get people to come back to them bc i know a lot of people banned them (myself included) to only buy american gas. only reason i've been going there now though is bc its closest to my house, not counting a crappy gas qwik??