I have a CQC and some extra CQC kits. Was going to install a kit on an A3 I just picked up to have two CQC AUG's. Why two? Because I really really really like the CQC and two is better than one.
It's heavy. No way around it, it's a pig, but the added weight changes the perceived recoil and muzzle rise. It's a great gun but might not be what you want if you're running around with it.
I could weigh the difference between a 23 slot A3 rail and a full CQC kit, but the CQC was intended to have an 18" bbl. If you've read on the CQC THEN YOU know that 18" barrels weren't made until well after the guns were sold, necessitating the use of 16" bbls and extended flash hiders. Therefore unless you have an 18" bbl, the ratworx adapter won't do you any good...
I also used to have a couple ratworx thread adapters, but they're long gone. I remember them to be a bit heavy for what they were.