i had the smae problem, on paper the mounting kit seemed like it would be perfect....when i went to pu tit in....it wasnt....the little tabs on the sides of the kit wouldnt allow me to insert the deck.....tried it upside down and right side up, no luck....i just ripped the two sides off the mounting kit (leaving the pocket and face plate area)...and then used the factory mounting bracket to connect my new head unit to....keep in mind this takes a alot of patience and a lot of adjusting...
im not sure why some cruchfield orders are working while others are not...i got mine only about a month ago and when it was delivered it said "xa & xb kit", i just assumed being that they didnt have install info on the car yet, that most likely the same kit was used for all scionms and they simply hadnt made a new wrapper for it......either way it seemed like it was close the whole time but never really fit the way i wanted....so i just gave up....and used my own way...
btw drilling the holes myself allowed my to push back the headunit a lot so the screen is completely flush with the rest of the mounting kit, only thing protruding is the volume knob, and it looks amazing....the first compliment i get on my car when people see it, bneside the car itself, is for the install....
in the end, it may take more time and effort, but drilling you own holes in the factory bracket, my be beneficial.....
here is some dudes write up on the whole thing from scion life...IMO his final look is terrible, but it gives you a visual of what i was explaining
HU Install
any more questions, let us know