I'm going to be installing an undertail on my 02 f4i, and I think I saw a good site that describes where to cut the plate mount and remove the junk underneath on this forum, but I can't find it now. Any links or help? I was just going to cut right above the rear seat lock.

also, I don't have a dremel, but can I just use a drill with a dremel bit? On my F3 I just used a hack saw [:@]

 

yes you can just used a drill with a dremel disc no big deal--cut the bastard about 2 inches in from where the stock "mud flap" attaches to the rest of the under tray. that will give you the most available trunk room