Hey nice!

For the rear opening, something along the lines of the rear diffuser on a race ready Skyline or Supra. I'll be more than happy to do something on photoshop so you can see what I mean.

As for the antenna, you could try a roof mount like the Foci and VWs use. I always hates poles sticking out of the fenders


2003 Ford Focus ZX3 "Tarmac" http://www.cardomain.com/ride/2352003