help! out of space and need to run a program!

[acidrane]

ok first off, im new to this forum and site. a friend of mine told me about it.

second, i have a slight problem.
my gf is a musician and REALLY wants logic studio. the problem is it requires 46gb of space to install. im not sure exactly how big her hd is but i rememebr seeing that she only had about 22gb free. given that the hd itself is not big enough to support the program, i was thinking of getting her an external hd connected via firewire or usb and running the prgram off that. my question is, is it possible to do that? is a simple plug n play or do i need to install anything on the drive before hand? any other suggestions????

ps shes using a mac book g4.

tia

vick