Getting one from 2nd hand car dealer is ok as long as warranty is given, try for those which gives at least 2 years. AB gives 3 years warranty so if the one you're getting is 2008, means there's remaining 1 year left, and of coz since the car is from AB, just send it back for a full check up before purchase. But since its still under their warranty, you've got no choice but send it back to them for service during this period as not to void the warranty. And do bear in mind they charge a premium even just for an oil change. Personally I've sent my E70 to Beemerholics in Sunway for servicing once before and I do find their mechanic is highly knowledgeable especially about the N52 engine. Another place which i've sent to before is another workshop in Jln 225 just behind Mobil which I sent to replace the faulty elec park brake switch, They are quite good as well as they specialize in continental rides, espcecially bemmers with the new generation engines and gearboxes.
From what I've been following, a fair 08 E70 3.0 should go for around $380k-$$410 depending on the specs & condition of coz. Try to get one with rear cam, power boot and HUD. But FWIW theE70's rear cam is below par compared to other German marques, or even the Japanese SUVs/MPVs as during the night you can hardly see plus the lag for it to activate when Reverse gear is selected is an eternity 5 to 7 secs.
The problem with getting a Jap recon is the radio frequency which is different from ours, so leceh a bit if you listen to the radio a lot. Plus the built in GPS on the iDrive is unusable here in M'sia as it uses a different "system'. UK spec ones are compatible. And of coz not to mention the one from AB of coz everything is usable from radio to GPS.