AST do some mean suspension, as far as I'm aware they don't have a set for EK9's? I spoke to someone when i was at Powerstation from AST about 6months ago and they said they don't offer them for the EK
However on a smaller budget im currently using MiesterR Zeta R's with 10-8 Springs, they are good but for track use id say they need harder springs, looking to change mine to 14-12 until i can afford some higher end suspension, However if you don't already own them you can order them with your own choice on spring rates on