the stem cushion is very important piece of the strut assembly. in the daystar lift you replace the top plate on the strut. the oem top plate has a mount that is set in rubber. this mount gives as the suspension moves up and down. it lets the strut move outward as the suspension moves up. since you replace the top plate you have to recreate the rubber mount. the 2 stem cushions (one above and one below the top plate) make a flexible mount for the top of the strut ... just like the oem top plate. mind you this is all going on the fact they are put together right. the shop that did mine forgot the cushion that goes under the new top plate and WOW that sucked. back out of my garage and BANG. metal hitting medal cuz there was a cushion missing. got it all straighted out and she drives like a dream.
i hope that answers your questions and i hope i got all the info right. i just installed a daystar 2.5in kit (kj09115) and i love it. i have a crd so its really the only option for me but wouldnt have done any other lift. its also a little work to put in so if you are not good with tools and cars i wouldnt try it. i could have had mine installed for $350 and its almost worth it but i dont like other people messing with my jeep
. one of coolest things on this lift is the front spacer. it has 2 built in gaurds. a big bumper on the outside so the ball roint on the upper a-arm hit the strut (very important) and on the back side there is extra padding so the spring doesnt hit the body.
as far as tire alignment goes ..... i took mine to a dealer yesterday and got the front re-aligned. it was 49 bucks and they said it went just fine. no issues at all and i still have a little adjustment left. not much. they said a very little.
i would say the daystart is the way to go. i the ride is the same (minus alittle extra body roll) and the parts really look quality.
hope this helps