It's definitely not just Lexus - The sad fact is no matter what car you buy (unless it is an exotic with big waiting list) the first year depreciation is almost vertical. Also don't believe the depreciation figures for Mercs / BMW / Audi etc because if you dig deep you will see they are just as bad. The figures quoted don't take into account all the optional extras you have to pay for to make the car resellable. So you may we ll get back 60% of the value for your E Class in three years apart from 2 small things :
1) that someone actually wants to buy it :P
2) you will have had to have added satnav, leather, CD, sunroof, parking sensors, auto box etc to make is desirable and you will get 3/8 of sweet FA back on them.
I speak as the man who paid 33k for a BMW 330i in "desirable" spec and got back 16K a year and half later
So be prepared to keep cars, especially expensive ones for minumum 3 years....I certainly plan on keeping my GS for a LONG time :D
Specifically Telephoneman - I suspect you may have got offered a whole lot more against another Lexus....
BTW - Parkers say you should get £30500 for a part ex on your GS....
Parkers Valuation