I am looking to replace the wheels on my 1997 LS400 and after searching and reading this forum am getting very confused about the offset I should be looking for.

It appears that earlier LS400's (pre 95) had smaller brakes and so the offset may have been different from my 1997 model.

I have looked at the website for Rochford tyres in Southend and they indicate an offset of 38-45 however there are at least three people that have ordered wheels from them and then found that the wheels do not fit over the larger brakes.

So basically before I go ahead and order the wrong wheels does anyone know for certain the offset of the standard wheels on a Mk3 (1997) LS400?

Standard Toyota wheels are usually marked with the offset -- probably ET50 or ET45.

You need what the Americans call "high disc" wheels to fit over big calipers. As a start, look for wheels which will fit a "UK" or "US" spec Supra with the big 4-piston front brake calipers.