Just the lower cups. Back in the dark ages when I ran all Losi and everyone else ran AE (now it's the other way around, I guess I'm still the nonconformist), we used to buy the upper collars and throw the cups away (we'd waste the collars). Who knew I'd need the cups. You have to work the AE springs onto the cups slightly, but it is an improvement.

I run AE springs with Losi bottoms. They are much more liner when you can keep them square and off the shocks. And before I stir the pot too hard, I want to state without equivocation: THERE IS NOTHING WRONG WITH AE SHOCKS OR SPRINGS.

However, any spring that binds/drags on the shock body is bad.