FWIW, I did a successful build following the manual precisely, and I've never noticed the wires through the vent slots.
To each their own- don't forget it's the music-
Crack/Speedball, SEX 2.1/C4S, Bryston BHA-1
Sennheiser HD600/Cardas cable, Beyerdynamic T1 2nd Gen, Hifimam HE560/Hifiman balanced cable