Looks like DIY upgrades for under $20.00.
Some of these can help, but that's mainly if you've got the patience of well... a sniper. I've tried a few of these mods throughout my years, when I originally started with a UTG M324 (The original one). The only thing that I think you should be careful of is that packing into the actual stock. Fortunately majority of these problems us Maruzen shooters don't have to worry about, because that's already packed solid. But for the hollow frames I can see how it would help.
To answer your question, I read through the whole thing and didn't see anything about fishing line tests. All the guy talks about is how to upgrade a stock MK96, which I give him credit he more or less fixes things that the factory fails to fix in the first place. Which is great if you're a handyman, but if you're like me then you just like to install things the way it's supposed to be and fire it. That's about the extent of my knowledge, I mean yeah I know the basic diagnostics on all my stuff if things don't work correctly for the most part. But I still have to look up stuff like this.
I've personally done the teflon mods before, and yeah it helped for the first mag or two, but then the teflon started ripping and would fall apart in the barrel.