Suspension question should be in SUSPENSION thread
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I don't see why you would have a problem fitting 17's if the car is dropped 45mm or even 50mm. I have a 45mm drop with 17's and it's fine and didn't even have a problem at 50mm.
You put 17's on your car without lowering, it will look as if the car were on it's tippy toes, but other than that .. your car will look better with 17 inch rims. It's your decision.
I put rims on before I dropped my car. Here's a picture of the before and after.
