Hi Tanya, I personally haven't had any experience with wide arch kits on a 1 series however it is quite commonly known that you can find after market body kits on a lot of cars don't fit particularly well and can require quite a bit of fettling and fine tuning. The difference is the aftermarket kits tend to be a lot cheaper than any OEM stuff. Some people try and build their own kits of OEM stuff by buying bits of ebay one at a time but it can take a while and may not come in the right colour too.