The E60 530d/535d had the M57 engine for it's entire life span so there should be no issues with the timing chain. The engines didn't change to the N57 until the F10 arrived in 2010 which is the one with some timing chain problems. I'd go E60 LCI if you can as it got the newer and smoother ZF gearbox. Seems to still be bit of a premium for a 535d over a 530d but if both cars are like for like (condition and spec) then I'd pay a little more for the 535d. I have an F10 530d myself and love the car but sometimes I do think I should have went for a 535d.