One thing to realize about the EDFC ACTIVE is that it is not plug and play. It requires tuning. The stock settings upset the balance of my Z to the point I almost lost control. The stock settings have very gross adjustments and our Zs need fine adjustments. I’m still playing with it but I don’t get a lot of time to drive my Z due to my job. I only get to drive my car 3-4 months out of the year. The EDFC ACTIVE has a lot of potential but you have to be willing to tune it. That being said I would get the EDFC ACTIVE PRO over the other EDFC systems even if you only plan on making manual adjustments. The PRO version has a lot more capabilities than the other systems. One negative thing I have to say about EDFC ACTIVE is the GPS for it sucks. It is not responsive enough to be useful hence why I recommend the PRO version which has speed input directly from the car. Also the PRO version has the ability to wire in 2 remote preset switches which I’m very interested in.
I have no experience with Airrex but I did take a quick look at their web site. Even if their air suspension is track worthy I would be wary of the added weight due to the air compressor, air tank and associated equipment. Just my
Hope all this helps!