Replicas tend to be heavier too, so it will hinder performance and decrease mileage.

That being said, I did not buy a 3.0i to go real fast, and the cost of oem's are so high, that I will probably end up buying a 20" replica unless I can pick up a set of oem at a good price.

I purchased a set of 18" M-parallels for my other BMW and it has worked out fine.