The soundtrack of this movie uses NEW WAVE and HAIR METAL from the 1970s and 1980s. All the tracks are as follows:

Venus by Shocking Blue

The Great Curve by The Talking Heads

Baby, Please Don't Go by Paul Revere and the Raiders

I Ran (So Far Away) by Flock of Seagulls

Cum On Feel the Noize by Quiet Riot

Don't Fear the Reaper by Blue Oyster Cult

Gut Feeling (Slap Your Mammy) by Devo

52 Girls by The B-52s

Except for the DEVO song, which I have not heard, I have heard all the others, but none of them are the same. . . The one by DEVO is probably pretty bad too, but I don’t rule out the possibility that I remembered it wrong. I also like the purely instrumental part you mentioned. It is very different from the overall soundtrack style of the film. Maybe it is not included in the OST. There are many people asking about this song in the IMDB comments about this movie, but no one knows about it, haha. (Some people say that the author may be named James S. Levine, you can check it out).