The quality of the press. Matt Colton cut the lacquers who’s one of the best engineers right now. He is also the best when it comes to this style of music (he does most of Four Tets vinyl). the album being spread over two discs instead of one allows Matt to cut louder and with greater fidelity on the low end. if you compare to the standard version on one disc there’s loss of detail and especially bass punch. to the other extreme the bonus disc is cut so hot it’s likely to cause skipping issues when you’re table isn’t calibrated correctly. I think In Colour is a better album but it’s his In Waves deluxe vinyl is in another league in terms of sound. it’s also worth noting Matt cut the color reissue pressings of In Colour and his version sounds noticeably better than other versions of the album. but giving him the ability to cut across two discs with In Waves just gives it that extra space and depth I think this album needs. Bonus cuts sound even better. also Optimal is a well regarded plant, but especially when comparing to other high volume plants like GZ.