x5 4.6is advice for uk buyer

[stevedaff]

does anyone know what common problems to watch out for on 4.6is x5 2002 ..with 70000 miles on clock.car i am looking at has had a full engine rebuild by bmw due to timing chain ..this is gaurranteed for another 12 months..is timing chain /tensioners a common problem
car also has 12 months independant warranty on parts and labour and 3 mot test gaurrantees ( basicly if car fails mot test on anything except tyres exhaust and brakes its covered for 3 years)
advice appreciated
what drive train problems occurr thanks