Yamaha DTXpress/DTXplorer/DTXtreme

Hi again all, 

OK, so if playing along with CD's is one option, and most of the 
songs on the DTX are kinda lame, is a MIDI device the way to go? Like 
the MDF3?  Is that the way to get good practice material? And since 
it also records, it will back up the DTX brain as well.  I have to 
admit, I know absolutely nothing about this MIDI stuff.  I'm trying 
to find everything I can to read to learn more about it and how to 
utilize it. Are folks here using MIDI devices and feeding it into the 
DTX for practice, and using those for recording as well? Can somebody 
point me to good reading material on how to utilize one with the 
Xpress set?

Any recommendations on devices to consider?  The manual suggests (of 
course) their MDF3.  And are there lots of MIDI files available for 
download somewhere to use? My brother-in-law has a JS-5 Jam 
station... is there a way to take the pre-recorded tunes off of that 
and put it onto a MIDI device like the MDF3?  And during playback, 
can you mute the drum parts with the DTX like you can with their pre-
recorded songs, or do you have to dump that onto the DTX and save it 
as one of the "user" songs before you have that kind of control?

Sorry for all the questions folks.  It just seems like it's time to 
take the next step with this thing (which might be a MIDI module of 
some sort...or am I wrong)?

Thanks in advance for any help/pointers you all can send my way.  I'm 
off searching the web again for more reading material on the subject.

Rolf