What makes Transmission IV by Porcupine Tree notable?

This release is significant for its extended track lengths, particularly the two-part "Moonloop," which emphasizes the band's experimental side. It contributed to the band's reputation for pushing boundaries within the progressive rock genre, garnering attention from both fans and critics alike. By 2001, Porcupine Tree had transitioned from a cult favorite to a recognized name in progressive rock. "Transmission IV" followed their acclaimed album "Stupid Dream" (1999) and showcased their growing ambition towards elaborate compositions, further solidifying their artistic direction.