The offset is +32 and these rims are very good for 300z brakes, better actually than original 300zx rims.
For comparison, 300zx rims are 16X7.5 +45.
There is absolutely no problem if you use coilovers.
These rims have 11mm bigger backspacing than stock s13 rims so basically you need that much space between your stock spring and stock wheel. Measure and You will know for sure. I think there should not be a problem. Even if You need a spacer it shouldn’t be bigger than 5mm which You can get everywhere for like $10, car will look even better and don’t need to change wheel lugs for longer. Cheers!