I've heard that the only setup that creates a hassle for an after market radio in an RX330 is those with ML audio systems. If you just have the OEM radio, you need to get the Metra Double Din Kit so you can fit in an aftermarket stereo. You could do either single or double din. Just get one that has bluetooth at least so you can pair a smartphone to it for music and calls. These units go anywhere from 100-1000 depending on what features you get. Just do some research and then call someone at Crutchfield for example and try to narrow it down to the unit you want. Might as well change the speakers and add an amp while you're at it.