Dustin, the bottom screw on the 510 connector may be loose causing the top blocks to move and touch eachother when you torque down.
At any rate, I just got my KFL+ and set it up Friday. With the AFC screw all the way down (airflow wide open) it is slightly airier of a draw than the og KFL. Even better with the AFC screw removed altogether. Honestly I don't know why anyone would want a tighter draw than stock on this, so I didn't even experiment with tightening it.
As far as the new fill screw, I like that it no longer leaks but I still like the old fill hole and screw better. The old style screw was almost self-guiding and it seemed easier to fill straight from the bottle (no needle tip). I'm finding my
juice "pools" up a little more in the deeper fill hole than on the old one. Nothing major but something to note. I still don't use a needle tip.
All in all, I do like the new KFL+. Is it worth selling your og KFL for $70 just to cop the newer version? I wouldn't. There are minor improvements, but the KFL is almost perfect to me as is, "tight" draw and all and the upgrades are just minor. The draw difference isn't drastic, but it is looser. I did sell one of my KFL's for $100 to get the KFL+ and don't regret it but I have 3 KFL's. At least at $100 you break even to give it a try.
As you can tell, I am a full-on
kayfun convert and just love these
tanks. Easy build, no leaks, best flavor and to me they even blow clouds. Just gotta know how to build it right. I don't think you can go wrong with any version of the Kayfun. My only advise is to put the coil as close to the airhole as possible without shorting it. Bigger clouds and more flavor.
Btw, I usually do 28 gauge micro and cotton around 0.8 ohms but I'm currently experimenting with a 1 ohm wrap. So far I'm lovin it.