nismo lsd install question

[Liquidus]

I am having a nismo lsd (w/o OE LSD) installed. The dealership first said they could install it no problem but after i dropped my car off they called me and told me they couldn't do it right then. They said that there was some sort of washer or shim that the needed for setting the preload or something like that. I talked to a few different people and the told me different things.They also said something about having to get 13mm bolts instead of 12 mm, thats mentioned in the instructions but its not clear enough for me to know exactly whats up.

I ended up talking to the manager about what was going on and they said they would look into getting the parts that are needed and call me back when they have more info.

Should i have them install it or should i find someone else. Does anyone know what these parts are they are talking about. I am having some serious doubts about them and don't want to risk having them mess it up.

[s13sr20chris]

there are shims but they dont always need changed. the dealership should be the best ones to fix the car. they should have all the goodies. when i do them i just slap everything in and check the gear mesh. if the contact area is good i let her rip.