55mm is stock offset. There's a "stock wheel specs" thread around here somewhere. Your wheels will fit, but they will poke outside the fenders. On a daily driver that sees no track time, I would recommend an 18x8 +45-50mm which will get you pretty close to flush.Is someone 100% sure what the offset on the 2018 Elantra Sport Turbo with the 18x7.5 wheels? Also, I have a set of 18x8.5 +38 rims that will go on car if they fit. For offsets I have heard everything from 55 to 45 as stock offsets.