Originally Posted by Dustin@Z1

These are technically not a S-Tune item. The are not found on any 370Z factory and are a JDM only accessory. They will fit all 370Z models including the NISMO.

We installed a set on out shop 370Z about a year ago. Installation is fairly simple with basic hand tools. One brace fits under the front cowl, one behind the occupants in the cabin and one one the rear subframe.

Here is a link to the install we did:
Nisom Suspension Brace install - Z1 370Z Shop Car

We generally keep a set in stock as well.