Yes, it’ll run the ‘normal’ backup routine on the old server, then transfer it to the new server, then run the ‘normal’ restore procedure.
The difference being the ability to set a number of imports off in one go and monitor their progress.
The tool also GZIPs the tar before sending it over. The gzip operation means you need enough space for the tar+gzip while the gzip file is being generated. This is often where the disk space failure occurs since often the gzip compression will only compress the file by a couple hundred megs and thus you need enough free space for essentially the disk usage of the siteworx account X2.
Having more memory will improve the performance of tar/gzip but it won’t necessarily cause failure unless you have abysmally low memory and the OS is running out of swap space.