wilwood offset backspacing wheel rim fit

I'm ordering a new 2019 Mustang GT premium with the standard 18x8 wheels/tires. I would like to change the wheels to something a bit more unique. What is the offset of the factory 18x8 wheels?

I have a 1992 Mustang notchback that we have been working on. Has the 94/95 spindles and hubs, and we added the big brake kit (12.88") from Wilwood for the 1994+ mustangs. I'm trying to find a rim that will fit this setup with the correct backspacing and offset. Has anyone installed this kit on...