hole in the bumper is for a tow hook that screws in, lost the plug for it a while back. i build custom s2000 parts on my s2000 for people who cant bring their cars to me. thank you very much for the compliment! came out very clean. wont know how it sounds until he installs it, i sell the parts un used. their car is a supercharged s2k so hes running a race header, as far as i know and tanabe exhause cat back so all that will be in the system is a resonator. it should sound awesome.