I have a 2003 Rockshox SID and oil/fluid leak at damping speed adjustment knob (buttom right side of the fork). It leaks oil/fluid whenever I set the damping speed at slower speed (by turn the knob counter clock wise). Now I had to turn the knob all the way up in order to stop the leak. But the fork feels stiff now.

Is this something can be fixed at a reasonable cost or I should start looking for a new fork?

It's 80mm travel dual air fork. Can I replace it with something has 120mm travel?

Thanks