From what I’ve heard don’t get the zzp kit because it’s plastic. I got the transgo kit and used the 1 to 2, and 3 to 4 spacers (the 2-3 requires trans disassembly). It definitely helped firm up my 1 to 2 shift, which was very noticeable because my commute was mostly freeway, and the on-ramp was super short, so before I put the kit in there was an almost 2 second hesitation between shifting to second. After I put it in it was pretty quick and crisp. I’ve had it in for probably over 20,000 miles with no issues, and it still shifts great. The car is at 235,000 miles, so that should tell you a little bit.