Those pieces are supposed to come out yes.
When they say "material" they mean to cut away some of the core to make the holes bigger for the tubes. Is it required? No. Z1, AFE, and AAM all use rubber tubes to give you the option to cut or not to cut. Stillen is hard pipe, requires cutting.
Your install looks great!
__________________
PW 07 HR350Z R.I.P. Totaled by 82yr old woman 
2010 40th Anniversary 370Z
|