Just pulled the spring from my 2013 yesterday. Here are my comments:
-- Easy to remove -- maybe 15-20 minutes total. Would take a little longer to put back in for sure.
-- Huge change in clutch pedal feel! The main thing I notice is a lot more force moving through the engagement point.
-- Pedal does move laterally a bit now but this does not bother me at all.
-- Initial 5-10 mm of travel is very light or squishy feeling but again, does not bother me. Once you get to the important part of the travel, it is much firmer.
-- Just sitting in the garage, I think I like the feel better with the spring in place BUT as far as driving, I think removing it has helped since I can now actually feel the pedal pushing back on my foot in the clutch engagement zone even when accelerating of whatever.
-- If you think you might want a firmer clutch pedal, try this. You will notice a big difference and it is reversible if you don't like it.
--I still don't like this clutch. Would love to have the feel of my E36 M3 clutch instead (and I never really liked that one much)!