There aren't any bypass leads that I am aware of. You may be lucky and be able to buy the plugs/sockets from Lexus/Toyota and make one up yourself. Unless the plugs on the amp and head unit are standard types as used on other models, but I would've thought a supplier would list it if there was such a compatibility. Even the autoleads fascia plates for the mk1 are no good for right hand drive cars. So the only option there is the genuine Toyota items (Lexus don't list an equivelent so you need to speak to Toyota for Aristo items). Not many options on the wiring side unfortunately. I didn't bother making mine revertable if I sold the car. A head unit is cheap as chips to replace if I wanted to keep my existing unit when I sell the car.
oh fantastic
guess its out with the wire cutters then ?