New Spring kit last night...
I installed my 3k last night and put in a #4 at the same time.
Not sure which is causing the noticeable difference, but it drives soo much better. I LOVE the feel of the gear ratio and power levels.
I would explain it like this:
Before: getting dragged out of the water while slalom water skiing.
After: getting up on plane and actually gliding across the top of the water and being able to relax and navigate.
My idle increased a little so I know that the new springs are a little tighter. I'm heading out this afternoon to do a driveability test to check all of the adjustments as per Piers instructions.
For those considering installing a set, if someone installed a set in your truck and let you drive it for a day, I believe that dang near everyone of you would GLADLY pay the $125 rather than have them removed and replaced with the stock springs. YES, they make THAT much difference.
My install went well, but I'll admit that I was very cautious and bout had a bird when I got the AFC housing off and started to actually remove the old springs. This was virgin territory for me, I wanted everything to be right. I went slow, double checked everything, went step by step and lived to tell about it.
Attention: TDR Forum Junkies 
got the kit in today, and I knew everyone has said how great it was and so on but I had a hard time believeing changing a couple of springs would make all that difference, but its all true! the truck feels better all around and ... 
). . 
You guys keep bringing this up and I'm gonna have to drop $125 of my hard earned money!
Says he knows the mileage went up too because he is already past the miles per tank he usually fills up at. We'll see. He also had the cat removed and changed to a straight through muffler today. He's coming around. We'll be looking for transmission parts pretty soon. 
(maybe?). 
