Here is what I did and why I did it.
I looked at the standard mount at the center intake but decided to put them in the brake cooling ducts. (I used 3M permanent double stick tape on the bottom of the brackets to hold them into position. [Radio Shack]Make sure you first clean the plastic with rubbing alcohol to ensure a good clean area to stick to.)
I wanted a fairly stealthy mount and did not want the jammers protruding out the front. (My original idea was put them in the center intake and to cut a small section of the plastic grate and recess them to be even with the fender. So if this is your position of choice I would recommend recessing them.)
The brake cooling duct however puts them closer to the headlights where I think the most reflectivity is. (Since I do not have a front license plate and my car is dark I think the logical LEO aiming point will be the headlights.)
Since the included jammer mounts are limited in their application I decided to fabricate some new ones out of aluminum. I then ran the wires through flex tube piping and through the firewall grommet. I took the ground off the ground pole located in the area near the firewall grommet. (See picture)
Power is from a Red wire with white line, (Switched), from the back of the fuse box located under the passenger side dash.
I wanted the On-Off switch near the SMG handle so I could quickly access it with out looking. If you move straight down a few inches you will note a small hole. The speaker is mounted on the other side of the plastic there.
Also under this plastic I put the Blinder connections so I would have easy access in the future if I need it. There is plenty of room.
The hardest part was getting the SMG handle off. Just pull straight up and pull like hell. (Watch out for the rear view mirror though.)
Hope this helps any future M3 installers.