i used to run the alum bulks on my maxx and found the new grey plastic bulks work better. i had indegy front and rear and after every qualifier i had to retighten them to the chassis.this is even useing lock tight. i have about 3 sets of front and rear i wount use cuz of this. screws broken inside of them cuz of them backing out. not one problem with the grey bulks after 6 races.