if your buying just the arms, i have spindles from a venture that are long tube and use the stock upper crank arms that dont stretch like the viper/rx1 aluminum ones. if your going to be painting stuff, i have a rh trailing arm that is long tube as well but is venture brown color, same physical part as a viper.
also have some wider rods for that sled if your doing some painting that will make it wider. or i can sell you extensions to make it wider.
still waiting on the shock mounts for viper shocks though.