Is it safe to assume you'll be running 40's on your rig?I'm doing a JT with the Evo COs' without the double throw down. After talking to Evo my understanding is the non CO rear spring setup may be better if you plan to tow heavier loads. I'm trying end up with a JT that can play in the rocks or be an extreme overlander. Going with Dynatrac Pro 60/80 axles to make it harder for me to break things. I will have an Overland Atlas topper (400lbs) on it at times and possibly tow a lite weight dirt bike trailer . Won't be towing the trailer in the rocks and won't be doing extreme crawling with the topper. I know I might have to play with the rear springs till we get it sorted. I'm sure it going to be a fun learning adventure. Call Evo and tell them what you're trying to do with your JT. Between Mel and Eddie the have a lot of input