Couple things to keep in mind:
* The Sakura Zero shocks are shorter than "normal" touring car shocks, so when using another brand of springs you need to that that into account if you don't use the other shocks as well.
* If you use other brands of shocks you either have to build them short (put a 4mm spacer inside the shock body to limit travel) or get the +4mm shock towers.
* Some brands of springs are progressive (they get stiffer the further they are compressed). When you set your preload or use them in any way shortened you will typically be "losing" the softest part of the spring.
* Spring rates are normally posted as straight compression rates. When you lay the shock down (change the angle the shock is mounted at) you change the effective spring rate. A vertical shock is "harder" than one at an angle.
* The oil you use impacts your spring and vice versa.
Scott, Grant and I all race at the same place in the same class. All of our cars are setup differently as we all have different driving styles. While our goal is the same (Winning!) we've all taken different routes and monetary outlays to try to get there. That's the part that needs to be focused on here. There isn't a right or a wrong, just ideas and implementations. What works for you may not work for someone else. What is working for me right now probably won't work as well this summer when the track goes from it's current high 60Fs to high 90Fs. It's all about making it work for you.