Well I'm sure they're almost all true!
Oh and crazywakerboarder, don't feel bad I did the same thing trying to find my amp the first time, I even tore out my back seats!
Would a 1990 LS400 also have it under the front seat? I need to replace mine or repair it.
The amp is located in the trunk, mounted underneath the (rear deck)on the driver's side. If you need an amp I have them with warranty.