Information on the quality of FTK's?
I know what FTK's are, and I know what purpose they serve, but my question is, are they worth it? I'm buying a gun second hand (I'm in the USA) and he's put a Guarder FTK into a Marui AUG, so these are basically new internals. I've Googled this, searched other forums and found almost no info on them. Anybody have any experience with these tune up kits? Do they help preformance? Or do they hurt longevity?