Hi all I stumbled upon this plug and play amp, the LS400 is listed in the PDF as compatible.
I would buy one right away except it only lists 1995 onwards ls400's I have a 1994 :-(

Take a look
It's the THA Series Amps

http://www.blaupunkt.com/uk/amplifiers_110.asp

This page shows the adaptors
http://www.blaupunkt.com/de/download/PnP_a...iste_250407.pdf

Nice find. I too have a 94 but an import and the DSP section of the amp failed, did this cause problems I had to fit a new head unit ( including the facia convertor) then run 4 screened speaker cables and the sub drive into the boot then connect into the existing speaker connections, fit a new sub amp ( had to lose the 6 disc changer so mounted the sub amp in it's place) which had to have a 2 ohm output to match the Lexus sub.
Luckily I'm an electronics engineer so not too bad a job, sounds nice after setting up

Steve is an electronics engineer??? Do you fancy fixing my dash? Name a price

He's alright on dashes, just don't ask him to fit a fridge......