No resistors needed. Direct replacement.
I'm not familiar with the W126 cluster, but the W124 cluster pictured has the late model light guides transplanted into an early model cluster.
There's also some plastic around the two bulbs that needs to be cut out to resemble the improvements made on the late model cluster.

If I remember correctly, the bulbs used were the cool white option. Several other colors are available.

You're right, they are too bright unless you dim it a little.