Check some of my previous posts and search for others too. Buying wheels for these cars is a nightmare (huge front brakes). You need to have enough spoke curvature to clear the calipers, and thats something that isnt spec'd anywhere. You will likely need spacers if the spoke dont curve enough.
The offset range is also very tight with 8" fronts. Theres not a lot of room in there! Tiny bit too little offset and theyll stick out, too much and theyll hit the strut. If you need spacers to make up for spoke curvature, that will of course alter the offset too. You should also add the extra length to your lugs if you use spacers.
BTW, You'll need new lugs for sure. The stock ones are specific to the stock wheels.
Your best bet is to buy a setup that someone else has shown fits.
I have 18x8 AMG replicas all round, 225 255 tires, 5mm spacers on front, 28mm front lugs, 24mm rear lugs. I have about 2mm of caliper clearance, the wheel is right at the edge of the fender well (any more and it would stick out) and clears the strut by about 5mm.
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