From my WJ days when I had mine with a 4" IRO with Longarm's
They all have there pro's and con's
Claytons is the best you can buy, But extremely pricey and extremely time consuming to install.
IRO Lift Kit every piece is hand made in their shop extremely helpful and knows the WJ very well, You can get discounts for being a member on the Green site. Upgrade to the Bilstein shocks or you will regret it. Also order the adjustable front long arms or you could run into suspension alignment issues.
Rough country seems to have fixed some of their issues from when i had my wj back in 08-11, Appears they are still using rear shock re-locators IE the shock sits to the side of the mount on the axle. their shocks not the greatest.
I would use JKS's trackbar with Kevin's offroad Durometer bushing's WJ's have a way of eating trackbar bushings.
at 6" you will need a new front drive shaft no question and a rear possibly or your gunna get drive train wobble.
Carolina Driveshaft was what i chose they were the best!
My WJ on 4" IRO Lift with long arm's and 265/75/16 Duratracs
Depending on your year you might have a reppa reppa joint which turns out like this at 3"