Well, I got the FEV V4s in last week. I have one, all original configuration, with a Ti build on an Invader Mini that I use when I go outside. I just built another only this time I did some moditfication. I doubled the size of the air slot before I cleaned it and built it for the first time. A Dremel with a burr is a handy tool! I also ground the locating pin so it sits flush with the tank body instead of sticking out a few mm. I went against my norms and built this one with 8 wraps of 28 gauge NI200, I normally use Ti or SS316L, and it came in at .112 ohms. Loaded it up and put it on a hand built, DNA40, low tank, mod. Holy clouds Vapeman! And that's at 20 watts and 420F.
I have noticed that the flavor seems muted compared to the V3, but then my V3 has modified air flow as well. I'll wait and see how this latest, NI200, build ages in over a tank or two.