Hey Mate
Many S30 owners run 7” - 8” wheels with 0 offset and they remain just inside the guards, pending tyre choice of course.
I run a couple different wheels sets on my 240z
Road wheels are 15x7 0 offset with 205/60/15 tyres and they stay completely inside the guards.
Track wheels are 15x8 +4 offset with 225/50/15 tyres. They are just inside the guards but I have been getting tyre scrubbing on the wheel arch lip under heavy cornering and over bumps. Hopefully this will get rectified with rolling the inner lip of the guards. Its also worth pointing out that I also have about -2.5’ camber which pushes the tyre out slightly compared to standard.
Im assuming you intend to have flares? As I don’t think it is legal to run the tyre proud of the guard?
I’m not sure what you mean by m and l type discs?
I can’t see a link to a website?
Personally I wouldn’t go for your chosen offsets but, I’m not sure I understand the look you are trying to achieve.
Where are you located? Maybe try and catch up with some other z owners and look at their wheels, before laying down the cash.
These photos are with the track wheels the night before the - camber got dialled in.