That thing looks deadly. No, really, you should have somewhere on the gun that is bright orange or green or someone might think that thing's for real. It looks like, from what I can tell from the videos, that it is very versatile and functional. By the way, what are the ranges on both?
Okay about the stefan drilling, this is how I drill mine. I take a regular drinking straw (just get one from mcdonalds) and mark 3/4 in. up the straw. Than, center the straw on the stefan and twist it back and forth. Go down to the mark you just made and take the straw out. get some tweezers or needle nose pliers and rip out the excess foam, and you're done!
I find that this greatly improvers the range and accuracy in my guns because it seems to blow the dart up like a balloon so it has the perfect tightness in the barrel. This is also good because even when the stefans get squished down, they will still blow up like a balloon in the barrel and have perfect seal. Hope this helped.