Yamaha DTXpress/DTXplorer/DTXtreme

hello, i'm new here and about to buy a dtexpress II (i'm pretty sure
anyway). Unfortunately there is nowhere within a hundred miles of where I
live that stocks all the different edrum kits to play and compare, which
sucks obviously. So I am going to get one sent, and as a result of a weeks
worth of exhaustive research, I seem to have decided on the dtexpress II but
wanted to check a few facts with you guys before i go for it:

Am I right in saying that there is no way of assigning drums to discrete
outputs, so that (for example) you can let a live engineer balance your kik
and snare the way he feels is right from front of house? does that mean it
is literally stereo only output? Does this mean that during a soundcheck, if
the engineer is moaning that he's not getting enough kik, I would have to
start trawling through menus and punching buttons to turn it up?

There are two things that i would like to use midi for, can i just briefly
mention them and see if its possible? here goes; firstly i would like the
ability to play a drum track and transmit the midi data to a sequencer for
firing better sounds from a sampler at mixdown. I'm sure it can do this but
is there any limitation? does it transmit absolutely everything that it
recieves such as high hat pedal changes etc?
Secondly I would like to do the same in reverse, i.e. to allow an external
sequencer to play the kit from a midi file of me playing the song at an
earlier time. Is that facility good enough for live use? because sometimes
i'm required on guitar, and short of growing limbs this seems a good
solution.

One more thing, i've not managed to find out the extent of the
cross-manufacturer compatibility and because i am new to this lark i'm not
sure i fully understand what goes on. Could I replace those funny pie shaped
cymbals with a v-cymbal at a later date? Likewise if I wanted to upgrade to
a mesh head snare from a competitors range, is it compatible?

Lastly, I know this is a bit of a stupid question, but could I possibly get
some opinions about whether this kit is generally good enough for live and
studio use. I will be a bit dissapointed if i end up suffering from machine
gun rolls and stolen notes etc etc. I guess I need to cut through all the
marketing hype and biased reviews and ask some real people - is this an
interesting and fun practice kit, or is this a seriously decent drumming
tool? I really dont want to fork out for one of the kits that cost
three/four times the price but in fact dont sound any better, plus i'm a bit
of a yamaha fan!

many thanks in advance for any info