straightsix

I was only just thinking about this the other day!

I wish I still had my V8 as I would have added another to the number

Wet

Mine was running a UK cluster with no issues - a UK cluster is plug and play in a J-Spec. Maybe try another cluster (if you could borrow one) or speed sensor. Something doesn't seem right though....

Which Lexus badge as a GS....

Taking pictures is good in the absence of a dash cam - especially one showing the road positions of the vehicles. We used to have a camera in the glove box of the work's van as the company insurance wouldn't do anything without pictures of damage and the scene. Dash cams actually show what the sequence of events are - and are unfortunately becoming a necessary windscreen accessory

Sump and wiring will be different but it's do-able. As above though, why not swap like for like as you won't be gaining anything other than a Lexus badged engine....!

IIRC when I fitted genuine UK clocks, I did not need a converter. Are you sure someone hasn't just stuck a UK dial on a Jap cluster? EDIT: Ah - if they're UK clocks and you still have a converter you'll definitely need to remove it

Easy to remove in one lump if you have an engine hoist. take the bonnet off though (obviously!)

IIRC you'll need to remove the dash bulb too.

Pretty much. Some of the Lexus models have wiring running to the door mirror glass too but you wouldn't get that for the Supra!

If you've never had one, I guess it could be seen as pointless. Having had one in every Lexus I owned, it was the first thing I retrofitted in my Passat when I bought that. They prevent dazzle far better than a standard manual tilt mirror and in my opinion make crunching night time miles far safer

Page 128 of the manual here - http://www.mkivsupra.net/docs/repair/Electrical%20Diagrams.pdf

Try ebay for UCF20 LS400s breaking. I got a couple of sets in the past and paid no more than £100 posted. I always bought new discs and pads though

SC400 and LS400 props are too long to just bolt on. You'll either have to get a custom prop, or use a Soarer front section with a Supra TT rear section and swap the diff flange for a TT one.