That's an awful lot of data to send as XML. Remember, XML is basically a text file with tags to define each field in each record - very big result!

If you can, the best bet would be to generate a text file (either XML, CSV, DBF or whatever) on the web side - then ZIP it on the web side and xfer it via HTTP or FTP to the client (ftp would be best). Your client app can then unzip the file and import it onto the local tables.

Of course, if you can reduce the amount od data being sent (using time stamps), that would be the first thing to do no matter how you transfer the results. I had an app that kept track of the last successful transfer and only requested data modified AFTER that date.