I got home and no rain so I pulled a table outside and made a mess! I'm right beside a bike/walking path so I can only imagine what this looked like to passersby.
Anyway, I followed Letmebleed's thread and used that same cutting wheel on my dremel and started to cut chunks off of the n filter. No photo (I'm sorry) but I didn't draw any fancy lines, I just started to cut it up. It left me with this after about 20 minutes.
There is freaking dust everywhere! Anyway, I then grabbed some sanding attachments and started to grind down the parts that still stuck out. This now is not big enough to slide in the new n filter. All I've done is taken the top layer off. I still need to either grind out the thickness of the shell's filter, OR cut the aluminium filter to sit on top inline with where the old one was. For fear of no one talking to me again, I went with the first option. I grabbed my aluminum filter placed it on top of the shell and then I would note where I needed to grind out the shell. I did this section by section starting from the top, grind until it could slide down, grind the next section, slide, grind etc.
The I started to just find tune the cut to fit the filter in. It's needs some filler, especially under the front lip that sticks out but I think it'll do.
With the larger OD I had to take it right tight to the cyclotron ring.
Now I don't know if I need all of the aluminum that is sticking into the shell, but now I can start playing with location and how to mount the n filter and the vent system. I may trim a section out for more room. Not sure yet.