I'm currently looking at an athearn fp45. I can't afford the one with tsunami sound installed and was wondering if it's just better to install a normal decoder in it since I hear other drop in sound ones are garbage.
If you want a non-sound drop in decoder, the Digitrax DN163K1C is a perfect fit. There is a guy in Hong Kong who frequently sells Tsunami sound decoders on #bay for the Athearn FP45/F45 (I know, I have bought 3). Some cutting of the chassis is required as the DC chassis is different from the DCC version. You would also need a disc of plastic same size as the speaker to avoid a short with the chassis.