question about the RD-S rear bumper piece
 

I have a 07 550i non msport model. I was looking into getting a rear bumper to quad my exhaust preferably one that will allow me to keep the rear deflectors that are just below the mid portion of the OEM E60 bumper where the it looks like you can pull that portion off. 1. Can that piece be removed? Well I came across this RD-S style rear lip on CARID.com for the E60 and it has the cut outs for quad exhaust and it shows the Reflectors still on the bumper because its just a piece that goes in the place I explained. I called CARID and the sales guy said it was an overlay and I said how could that be because the OEM bumper is not a quad bumper and the OEM has that Lil lip at the bottom the goes outwards. And he said it was an overlay and I said how could it lay flush with the OEM lip at the bottom. 2. Would I have to cut that lip off and cut out a space for the exhaust to fit the passenger side???? Has anyone on this site used this bumper piece? Why can't I just pull that portion of my OEM off and attach the RD-S because the E60 rear bumper looks like it's a 2 piece anyway at that crease by the reflectors. Can anyone shed some light on this for me or am I trying to do too much work

2007 550i jet black non msport