I got the Ghea top spring retainers and 22 bottom cup retainers. You can also get top spring retainers that Traxxas makes but I decided spending $22 on Ghea was better than the $3 for the Traxxas stuff. Probably why I have little to no money.
http://www.absolutehobbyz.com/produc...oducts_id=8480
This is where I bought them from. They work perfect and I got them in two days.