Having said that... I tried to instal 10.3 on an external drive connected to my Tiger-running eMac today. It didn't get past the boot-up stage after the computer restarted following inserting the intstall DVD... if you know what I mean. Froze on the grey Apple screen. But I think that is because it was a PowerBook copy of Panther, which will only be installed on a PowerBook internal drive. It was to be used on said PowerBook, but wouldn't allow to be installed on an external FireWire drive. Beats me as to why...