http://www.beckerautosound.com/
Click on what's new for the radio manual.
Spoiler goes up automatically at about 75 mph and then back down at about 50 mph.
I am the strange guy. I have all the 1997-2003 owner's manuals and the radio manuals for the various years. Even 996, turbo, and GT3. People give them to me when they get rid of their car or I find them on ebay.
Tweeks wants $25 for a 1998 owner's manual. This is a few dollars more than Porsche's list price.