My sincerest apologies to everyone on this thread for never having replied to all of these requests. Obviously I have not been active in the club for some time now. However, one of you managed to reach my e-mail and it brought me back here. THIS is the supplier you are looking for:
Lexus of Pembroke Pines
16150 Pines Blvd., Pembroke Pines, FL 33027
1-888-373-4470
http://www.trademotion.com/partlocator/index.cfm?siteid=214082&catalogid=0
The ordering system is a bit confusing but the part can be found under INSTRUMENT PANEL then SOUND SYSTEM then WOOFER then PIONEER. Currently its $138.13 plus shipping of about $11.
These are absolutely the best prices I have seen for older Lexus parts.
http://www.trademotion.com/partlocator/index.cfm?action=getLocator&siteid=214082&chapter=ARB8910&appSectionid=2610&groupid=2644&subgroupid=6125&componentid=15364&make=20&model=LX%20470&year=2001&catalogid=2
As for the install instructions, I have lost them. BUT, I will try to find them online again and post back here.
Good luck all!