DO NOT DO THIS!

Also from a Mac tech guy, I do not at all recommend doing this, aside from the lack of its apparent utility. Moving the MacBook around and plugging in its internal hard drive while the MacBook is powered on is seriously asking for trouble.

Most likely, a simple Carbon Copy clone from a working 10.4 external drive to the pre-formatted internal is all that is needed here, although as other commenters have wondered, I am not sure why one would want to run Tiger on a Leopard-native MacBook.

Sorry, but this hint needs a "0" on the rating scale; I can't even give it a "1"!

SATA HDDs are hot-plugable, so that part of the hint isn't so bad (ignoring the fact that taking out the internal HDD in the first place is totally unnecessary)