I owned an LS400 for over 13 years and it still is without question, the best vehicle I have ever owned. So reliable, so luxurious and just so easy to own and painless to run.
Insurance and servicing costs reasonable and most Lexus dealers happy to give you favourable prices on parts and labour on older vehicles.
The LS430 is definitely a big step up in terms of equipment, specification and overall performance.
I now own the Mk 2 version of the LS430 which has the 6 speed automatic gearbox with kickdown facility, reversing camera and the 5 spoke alloys - the Mk1 is still an amazing car but the Mk 2 version is the one to go for.
Depending on age, mileage, colours and condition I have seen LS430s (Mk1 and Mk 2 versions) selling for between £2k and £8k
My one is very unusual as it's only done 45k miles and it's in mint condition.