I love the kit. I have not had to buy anything that did not come with the kit. I have removed both the front and rear track bars to soften up the ride. With leaf springs, you will not get the best ride out there, but I just look at it as a quirk of having a YJ. As for the SYE, it goes on a case by case type of thing. I plan on getting one eventually. If you go for the boomerang shackles or lift shackles, you may need one. If using factory shackles, more than likely will not need one right away. If you look at the YJ lift reviews you will see other options also, but I feel that you get the most bang for the buck with the RC lift. If you have any questions, feel free to contact me or post in the forums and you will likley get many responses.