Originally Posted by OptionZero

I am 100% sure SPL AND z1 are not the causing the confusion. You're missing what they (and we) are telling you. You also aren't reading the product descriptions right on SPL's website

Stock 370z has eccentric toe bolts to adjust camber and toe in the rear. There is Zero front adjustment. The flaw with these bolt should is that they slip over time.

SPL sells these SPC (note difference) to toe bolts which REPLACE the stock toe bolts and offer slightly more adjustment. They have the same flaw as stock bolts but they are a cheap option for non high performance use

The SPL ECCENTRIC LOCKOUT kit replaces the rear camber and toe eccentric bolts and ELIMINATES ALL ADJUSTMENT from them. They become "locked" in place, hence the name lockout kit

As stated in their description, this kit is for folks who have their rear adjustable arms, because THATS where the adjustability lies. The arms are more stable and offer more precise alignment capability, far superior to the oem eccentric bolts. So you get rid of the failure point of the eccentric bolts and gain the greater adjustment of the arms ....but you have to get the arms

If SPL suggest the replacement bolts, I'm sure it was because you were squeamish on the phone about suspensions mods and they figured you were being a baby again about suspension modifications in your sports car