The problem is that it requires quite a bit of research to answer your question, but I will give it a go:
(1) I am not aware of any 18-inch OE BMW wheels for the E36 Z3, so I suspect those wheels are not OE.
(2) Offsets for the 135i seem to run in the mid- to high-40s -- or about 8-10mm more than the Z3 wheel specs you cite.
(3) For 18-inch staggered fitments on 1 series, BMW specs 215/40R-18 front and 245/35R-18 rear tires
. The Z3 set has bigger tires
, particularly in the rear. You say that you are considering buying the wheels, so it may be that you don't plan to use the tires
The 10mm less offset (negative offset, mind you) moves the wheel/tire 10mm further from the centerline of the tire or further out. With the wider tires
, that will probably clear the suspension on the inner side (about 10mm more clearance but then wider tires
reducing the clearance), but I'd be afraid would rub the fender on the outer side, as the outer edge of the tire is moving out 10mm plus wider wheel (?) plus wider tire = maybe 20-35mm more?
If you are talking wheels only and would put 135i size tires
on, then it is just moving everything 10mm out plus half of the any greater amount of rim width on both outer and inner sides. With 8"/9" width on those Z3 wheels I believe they are going to be wider than 135i wheels, so you are moving them over 10mm (20mm?) further out.
So just estimating the numbers off the top of my head like this, I think the tire/wheel set won't work on your 135i. The wheels alone, with proper 135i tires
mounted, MIGHT work, but could very well rub on the outer edge/fenders.
Those are attractive wheels, but not worth the risk in my opinion.