I know, but that's just their standard PSU, so it has to match the most power-hungry device in the lineup.  The M13 needs about the full amount, the M9 only about 1200, so I'd be suprised if the XPS needs more than 1000.

I'd be grateful if someone could tell me definitively though.  Otherwise the only option is to buy the Modtone unit and return it if it doesn't work.  I don't like doing that though, as it's a bit mean to the supplier.....