128GB Limit Workarounds?

Hey all!

I recently found a deal on a 160GB HD & bought it to add some capacity to an audio editing machine (it's a dual 450 G4 running 10.3.7). I get the thing home & installed, then find that the machine only recognizes 128GB of the drive. I guess I had heard of that limitation, but didn't realize that it was actually a hardware limitation and that it applied to machines as relatively new as that G4.

Anybody know of a cheap workaround to be able to use the full 160GB?

I read about Intech's SpeedTools, that allows you to use the higher capacity drives, but that still costs money ($90, or $15 from OWC if I buy a drive with it.) I'd also rather not futz with a software driver and risk that an OS update might break it.

PCI-ATA controller? Which one?

Firewire enclosure? Which one?

Thanks!