[feuer]

I have Pre Lci e90 335i Mtech
The rear wheels are: 275/35-18 on 10" et25
It was rubbing slightly so I rolled the fenders.
The rubbing continue but only on the bumper and the inner liner.
(I'll post DYI of that separately)
Here is how I stretched the bumper 1":
I cutted a thick plastic plate following the shape of the bottom of the bumper.
Marked where I need to drill and attach U-screw clip.
On the Mtech bumper I needed two clips. I assume all bumpers are the same.
I installed the plate as a spacer between the bumper and where it fastens on the underbody.
Here are some photos. Last two are before and after.