Man, that is a piece of history there... If I am being honest, if you want to start having RC car fun again, it's probably better to shelve the SE. You don't want to have to scour every single time you break a part, and then end of competing with collectors on Ebay to get the parts. Even then, there are times you will have to buy old rolling chassis to get one part.

Honestly Ebay is your only outlet for parts for this car. Only other parts are on other cars and maybe some in dusty boxes on the top shelf in the older LHS. I see body sets come up from time to time, but they are pricey. Far as the steering, it probably is the servo saver, or maybe the servo itself is shot.

Optima Mid and Mid SE are pretty sought after collectors and there weren't a lot of em made.

Those were so cool. The object of many kids desire's- including mine. I just never had that kind of budget when I was younger. If I were you, I would constantly scour ebay for NIP and good shape parts, bodies, wheels, tires, etc., and restore that Optima Mid. It continues to appreciate, and restored/new builds get the most $$$ and it would be a fun project.

Go to the LHS or Tower and pickup a new RTR or kit that is cheap and easy to get parts for and get those RC jitters out. If you can only afford one or the other, I would be happy to make an offer for the Mid SE so you have some $$$ to shop with.