i own the GP Monaco rack and amp stands with Formula shelves and Apex footers. i have not had the Acrylic shelves in my system but i did set up an almost identical system to mine at the Rocky Mountain Audio Fest that did use Acrylic shelves and in my opinion i could tell the difference in ease and detail on the EMM Labs and darTZeel amp and pre.
the Formula shelves give you better clarity and a more refined sound. bass articulation and the 'boggie' factor is increased. these are subtle but significant differences.
one note; i have carpet over 6" of concrete. i bought lead shot and filled the posts expecting an improvement......wrong....it deadened the sound.....took the flow right out. only use ballast if you have a suspended floor and it needs dampning.
the Formula shelves give you better clarity and a more refined sound. bass articulation and the 'boggie' factor is increased. these are subtle but significant differences.
one note; i have carpet over 6" of concrete. i bought lead shot and filled the posts expecting an improvement......wrong....it deadened the sound.....took the flow right out. only use ballast if you have a suspended floor and it needs dampning.