I'm having the exact same issues in my fiance's Nissan Altima. If you don't mind doing a little dremelling to your mounting brackets, here's what I'm doing. I'm stacking the empeg on top of a pioneer head unit. I'm putting some washers in between the pioneer head unit and the brackets, to make the brackets spaced far enough apart to accomodate the empeg sled. Then I'm going to grind down the brackets where they indent so that the sled will be flat against the brackets. I will then proceed to mount the sled to the brackets using flat screws as pictured above in Tony's gallery. Next, I'm widening the holes in the bracket where it screws to the dash to allow for the brackets being further apart. This is the current plan...I'm halfway through the install...but I've seen this procedure done before in a Mitsubishi, so I'm trusting it will work. Unfortunately, she lives 7 hours away for the next twenty-some days until we get married, or I'd get some pictures.

Warning! Avoid the temptation to just crank the bracket as tight as it will go. You'll end up making the sled bow, which in turn will make it difficult or impossible to slide the player in and out. If you are installing only the empeg sled, the simplest thing to do would be to widen the holes in the bracket as pictured here:

(excuse the sorry photoshop usage)

Hope some of that makes sense. If I'm misinterpreting the problem...ignore all of the above.