Installing PIAA 510 on 08 XE (non-painted, non-chrome)

I have the base XE with the grey bumper and I was wanting to install a set of PIAA 510's. Has anyone done this?

I took a look underneath and there are a couple of issues. First of I can't seem to see anywhere to actually mount the lights, there is a whole lot of dead space behind the cover. Second it would appear like I would need to cut the part of the fender that tapers in and I am not sure how I would even do that cleanly (dremel?) (I think this is the part that on a chrome bumper it's a removable trim kit but on a bumper like mine it's molded in).

Any insights would be great.

Thanks,
Chris