I am running 275/60-18s on a 2001 SLT that was previously 16 inch rims. I’m using later year OEM machined aluminum wheels. They work / fit / look/ ride great. GPS speed versus Speedometer match is dead-nuts on the money. This wheel setup should have been stock. I think 255 is a little narrow for 55 profile. Your actual speed will be a few MPH lower than your speedometer speed, and your measured mileage will be higher, I believe. If the wheels are a good deal and you upsize the tires later this seems like a good upgrade but only if the wheels are worth the whole price.