So a current RX new is around £60k, no doubt a 2006 version was a similar price in real terms with adjustment for inflation, so a premium priced luxury vehicle which will have associated maintenance costs.
So at 16-years old clearly price will be much lower, and you may end up with a bargain, equally you may end up with just a money-pit. I think buying a 16-year old car is a different experience to keeping and running a car for 16-years. Bear in mind the average life of a car in the UK is around 13/14 years, typically they have not rusted away or have major mechanical faults, but just not economic to repair in rip off Britain.