The grand Nirvana
song on the album "In Utero" which contains tons of feedback and guitar muscle. There are many live videos of them performing the song (usually opening the concert with it).
"Radio Friendly" in music terms refers to a song being aired on a radio station that appeals to mainstream audiences.
"Unit Shifter" refers to a song that can sell copies of an album. Ironically it's the most aggressive song in the whole radio un-friendly album.