If the X3 has an X3 BIOS on it then you can install the disk without burning CDs. Just plug the disk in, then hold the white button on your controller while the Xbox boots. This will bring up
X3 Config Live. Select "Disk Tools - New Hard Drive Upgrade", then set up the disk as you want. Use "Click Here To Set LBA48 Option" to decide if you want the disk to be all F, or if you want all space over 137GB to appear as a G drive. Set "Use Saved Partition Table = Enabled", then select "Prepare And Format New Drive" to set up the drive.
After that use the X3 ftp client (username X3, password X3) to transfer your dash and apps to the Xbox. Make sure you confiure X3 Config live to boot from the location you put your dash in.
Finally, the most important bit. If either the F or G partitions on your new disk is larger than 256GB, copy XBPartitioner 1.1 to the Xbox, and run it to reformat the large drive. You'll probably need to do it twice as described in
this post. As a final confirmation you should check your cluster size on the F/G partitions -
this post describes how to do it. You need 16k clusters for partitions below 256GB, 32k clusters for 256GB-512GB partitions, and 64k clusters for 512GB-1024GB partitions.
Regardless of which method you use, you need to reformat large partitions (>256GB) with XBPartitioner 1.1 as described above - UnleashX and Slayers / AID can't format large partitions correctly.