Agreed that the change to SATA normally has complications, but it should not be an issue because the SATA will be installed as a slave initially as part of the procedure with the Migrate Easy software as it is a Windows app and Windows will be running in the original disk when you start the procedure.. This should allow driver detection and installation in the present Windows install.
The software is very user friendly and it won't hurt to give it a go.
One thing to note, make sure you do not erase the data on the 30GB disk until you are sure it has all been successfully transferred to the big one.
This leaves the option to use it as a slave and install fresh XP on the SATA.