A wheel has to fit your vehicle in more ways than diameter. Bolt pattern, centre bore, offset and load rating all have to match, and getting offset wrong can put the tire into the arch or the suspension at full lock.
We check the specification against your exact vehicle before anything is fitted, mount and balance the tires onto the new wheels, and fit them with the correct hardware.
If you are changing wheel diameter, the tire size usually needs to change with it to keep the overall rolling diameter close to standard - otherwise your speedometer reads wrong and the ride quality suffers. We will work that out with you.