it's actually an +20 offset but thats not that big of a difference and my car is lowered as much as it can be on these coilovers. cant i roll the fenders or pull them or something in case it start rubbing?
Yeah, you could roll the fenders, pull them, cut them, or just raise the car up. at that point, you're only going to get an answer from trial and error. there are so many different unknown variables at this point, unknown heights, weights, spring rate, bump dampening, tire size and pressure, etc. It's kind of like asking, "how hard do I have to hit a golf ball to get a hole-in-one?"
If you're dead set on these wheels, get a tire that fits it properly, a 235. then raise the car up a decent amount. something like 1-2in of wheel gap. test drive the car for a while, allowing for settling, and over the different road conditions you would experience. if you don't hear or see signs of rubbing then lower a little bit at a time until you find the desired ride height. I assume you're going more for looks than function? if you do rub, find the source of rubbing, what's actually hitting. if it's the rim touching anything, then you can get spacers, or take a grinder to the parts that are touching, that is, if there is enough metal to be able to remove some without altering structural integrity. if your tire is touching the inside of the wheel well, you can opt for a spacer to move the wheel more outboard, or more narrow tires. if the tires is touching the fender, then you can have them rolled or opt for a more narrow tire. Just be safe about it.
or don't, i'm not a cop.