Hi
The GS450h is a very well equipped car - on par with the LS430 in terms of toys including keyless entry/start and radar cruise on selected models. However it does have a few common faults - perhaps some due to age.
1) Calipers are known to sieze
2) Shock absorbers are thought to be under-rated and tend to start leaking - perhaps as early as 50K miles - the only replacement available is the dealer part
3) At around 100k the hybrid batteries start to fail - this is normally one or two cells rather than the whole battery - the lexus dealer will only replace the whole battery however a there are a few companies available who will re-condition yur battery pack for around £700 - £800
4) Some of the cars tend to suffer from creaking dashes - there is no real solution for this
5) There has been some incidents of corroded exhausts - at least one members silencer dropped off.
6) There has been a handful of incidents particularly on higher mileage cars (circa 150k) of failed hybrid pumps - This is normally down to a couple of bearings and can be fixed cheapily if you are handy with spanners - there is a full right up on this site ny member Hayne
I have been thinking about the gs450h for a while but cannot fully justify why i would want one compared to my 430.
If you decide to go for one - do all the usual checks - at the minimum I would say I would want a Lexus Hybrid Health Check Certificate - this guarantees the hybrid components for a year. If you can get one which has had the failed components replaced then that is even better. there is atleast one on AT which has had the Hybrid batteries replaced at Lexus for £3k - I would say if the rest of the car is ok then that would be a good proposition.
If you buy from am dealer - you can take it to lexus and get a full inspection done - if there is any failing parts you can go back to the selling dealer and ask him to rectify.
If you buy one which is less than 10 years old and under 100k miles (i stand corrected) you can buy a 2 year Lexus extended warranty for £995 which covers pretty much everything on the car.
I look on AT everyday - these cars are slow movers - so you have an advantage
I hope this is informative and good luck with your search
Now tell me do you still want one and why??lol