The Futaba RX I recommended above is Futaba's latest 8 ch FM RX and would be a good match for your radio. There are also aftermarket units available too. As for PCM, there is a slight advantage to them. They are slightly more resistant to interference and can be set up with fail safe settings if you desire. There are arguments on both sides of that issue. The best in favor, IMO, is that if it goes into failsafe it can be set to idle the engine and avoid a flyaway of the plane. PCM RX's also cost more and can ONLY be bought from the TX manufacturer.

BTW - if you are interested, and I hate to harp on the subject, but Futaba will be delivering a 2.4 module system for your radio this summer. Just FYI.