oh, crap. I guess it is time to get out the old measuring tape. I would suggest going down to a local scion shop and check it out in person. you know what your box looks like. and you will be able to see for yourself if it will work. I would also suggest bringing in your old box and try it on the car. I have had people come into the shop with wheelchairs and all kinds of other things to see if it would fit. try that and call me in the morning.
alright. 33 inches wide is no problem. you will run into issues with the height. if it is 18 inches tall it may not fit in the trunk. I was measuring with a yard stick so I could only get close. I know that is inprobible.