Selfishly, I would say buy the JRZs and get us to the highest discount!!
but below are my thoughts. Hope it helps!
In a similar situation as you. Currently I track TcKline DA with 600/700 and camber plates. After 30+ track days in the past year, they are due for a rebuild. That said, I have jumped in on this same Group Buy and will be getting the JRZ RS TWO.
My personal decision comes down to overall quality, ability to fine-tune settings and having the best damper that fits within CCA prepared class rules (in the event I decide to race).
My feedback on TcKline is that they are decent for the money and certainly capable in a DE setting. However, the JRZ unit is many steps ahead of the TCK. For example, I consistently hear from JRZ users that every click is noticeable. I can say first hand that this is absolutely not the case with the Koni’s used by TCK, especially as they wear down.
It all really comes down to your goals. If you’re tracking the car and really want something that can be adjusted to your needs or just want the best quality system, JRZ is the way to go. If you’re on a budget and want a solid track capable kit, the TCK is tried and tested. Unless you’re tracking, you are perfectly fine with a One way and do not need to worry about D/A; set it and forget it IMHO