I bought a new DCC equipped Spectrum 2-8-0 three months ago. More recently, I bought a new DCC Spectrum 4-6-0 with sound.   It's great, and the speed/acceleration/momentum control is so much better on the 4-6-0!  Can I bring the 2-8-0 up to a similar standard of control plus sound?  Can I buy a new DCC/Sound decoder and replace the factory-installed decoder in my loco?  If so what and where should I buy, and if not should I just add a sound-only decoder?   I'm new to DCC, so advice would be much appreciated!