Your tires have tons of clearance below the wheel lip that's why. Try dropping your car down a couple inches and see what happens. I am running an RMS system on my other car and have the same track width issues. It stems from these designs being based on 73 up track width. Bill will tell you himself that it will increase the track width.
Look at your car from behind. Are the front tires sitting out further than the rears? Unless your running some skinny wheels up front with high backspacing....say a 15 x 5 with 4" bs your track width will increase.
