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I believe your car came with 245/40/18 with offset 42 from the factory.
You are going to a thinner tire that has higher sidewalls. The 55's will fill your wheel well by an extra 1.25 inches. It will also cause your speedometer to be off by 5mph. When your speedo says 60 you will actually be doing 65. You will also raise the car higher off the ground which could affect handling and braking. I would recommend keeping the 245 or going a bit wider to 255. As for the sidewalls, I would go up to 45, but not 55. I have 255/40/19 and love the handling and the ride.
Here is a site that allows you to enter the stock numbers on the left and your new choice on the right. Enter 245 - 40 - 18 - 42 in the left column to get the proper starting point. Then play with the right side to see what changes a different tire will have.
https://www.rimsntires.com/specspro.jsp