Its not hard to find the starter on an m20 engine, but its a little harder on the m50. However, a good flashlight is all you need.
Stand at the driver's side of the engine bay with the throttle body directly in front of you. The starter is fixed to the engine block, roughly 2 feet down and 1 feet to the right of the throttle body. A large tube like thing. May be either black or silver in colour.
Removing the air hose that leads to the throttle body might help you see this more easily.
Hope that helps you in your threaded/non threaded question. This is the first time I've heard about this variation.