I'm getting a shimmy on my 93 1a2 that starts at low speeds and builds to about 45 then stops. The steering is a little less responsive that normal. If the car is sitting on the ground, I can kick either tire and see a deflection in the idler arm. What's the symptoms for a bad idler?
While you could have a worn idler as well, I am willing to bet you have a cord-belt issue in one of your tires.
It has been my experience that a low speed wobble or shimmy that goes away as speed rises is almost always tires.
Jack the car up and spin the tires. In extreme cases you can see the tread squirm.