Can it do them? Probably -- Though the large one will be pushing it, you'll definitely need the extended table.
Can it do these quickly? Probably not. My Taig can do about 0.1875 cubic inches per minute (6700 rpm, 1/4" 3-flute roughing end mill, 15 IPM/0.05 DOC). The first one looks like up to 80% of the material will be removed (if from billet) so that's going to be in the neighborhood of 4 hours, 15 minutes of milling and looks like in the middle there the part would need to be flipped over. The other piece, looks like maybe 40% of the material removed, so about 15 minutes in machining time.
The biggest end mill you can reasonably use on a Taig would be a 3/8", larger can be used but the machine isn't really rigid enough for anything larger.
The X3 is probably a better route if you have the money to convert it. Much heftier motor, and more rigid machine will allow you to use much large end mill's the then the Taig. Some sort of belt conversion will probably be necessary though considering the low top end of the X3 (~3k rpm).