My sanwa 2.4ghz wouldnt fit directly in, the Xtal (which is a button not an Xtal) is obviously in the way on one corner, the Steering plug is on another corner, and the aerial wire exits from the top of the case in another corner - making it impossile for a direct fit.
I was going to dremel the steering link a little in order to clear the steering servo plug - but then I realised I could just drill a hole in the side of the case for the aerial wire to exit from the side instead. So now I've not had to modify the car at all the fit my receiver in - which made me happy.