Well... I'm a little bummed. Asked at the reprap forums most of them told me that this is unnecessary and whatnot. which is probably true, since a new mk8 drive gear basically fixed all my issues. BUT: more force is always nice and since my current extruder is ungeared and I am now infact get missed steps (Way better than damaged filament!) and I also printed / ordered all of the parts for your extruder, I was still looking for drive gears that would work.
I found those: http://e3d-online.com/Hobb-Goblin-5mm
Will get back to you once I tested it :)