The advken gorge (24mm) I have is in daily use, the only thing I'd want is a smoother, more spread out airflow, looks like the c4 lp is exactly that.
I'd buy it if I didn't have too many.
I like intriguing small rdas, think that one is 24mm though. I can't remember and too litttle coffee to dig it up.
My problem, if it can be called that, is I now have 2 hobbies. One is expensive and still needs fine tuning, the other I'm in my happy place.
Somehow I've gotten to the point where I ask myself if there's a net gain when I look at a mod or RDA. Often I end up believing there isn't so I move on. I have backups, very good batteries, and all the accessories I need, with backups of those. $30-$50 adds up, and I'm often feeling I'd rather spend it on the HT as the prices, while higher, are way too good to pass up. C'mon, $225 for $2000 speakers!
I had begun to think about DIY, but I'm just not interested.