I own a E60 530i and would be glad to share my experience & thoughts with regards to your questionnaires.
BMW E60 530i 2008 - two type of engines available i.e. the N52 and N53 (direct fuel injection). N52 bought in by BMW Malaysia and used for E60 520i, 525i and 530i. The N53 though is a more powerful, it wasn't brought in as the fuel injector is sensitive to local fuel. Even in Europe, there were lots of related complaints on N53. Some of our members had rather bad experiences with their 530i N53. There isn't any solutions to rectify the clogging of fuel injector and each injector cost RM2k plus and you need to replace 6 injectors. So a word of extreme cautious here......walk away if the E60 is with N53 engine. Do a goggle search on N52 & N53 (problems) engines.
Prior to confirming to purchase the car, it would be good to send the car to any BMW authorised dealer/workshop and have them do a complete mechanical & diagnostic test (for RM180.00 only) and the necessary parts to be replaced.
1. Maintenance
Unless you have the previous service & maintenance records, put aside RM 10k to15k for replacement of worn and/or degraded parts (suspension system, water cooling system, auto transmission gear system). General service i.e. replacement of lube oil & filter is approx RM 550.00.(every 10k km for full synthetic lube)
2. What are the usual problems for this model
N52 magnesium engine tend to consume small amount of lube oil for every 1,000 km and that is norm according to BMW. There isn't any dip stick to check for lube level and any shortage of lube level would be display from the iDrive screen. The electric water pump tend to develop leak at 80k to 100k km. The other usual problems (I won't refer them as problems but the usual wear & tear) are the absorbers, front & rear upper & lower arms, brake disc rotors, fuel pump, throttle body and top cylinder cover which houses the intake ventilation system.
3, Best and affordable workshop with genuine parts in Ipoh area
Can't comment as I am not from Ipoh. However, we do have a number of members from Ipoh and guess they may response with their recommendations.
4. How about the transmission (gearbox) system durability (life span)
Auto gearbox is 6 speed (code ZF6HP19) from ZF of Germany. This particular auto gearbox is also used for E60 and E90 (with the exception of M5 & M3). The main complaint of ZF6HP19 is the infamous "gear slam" (goggle for details) and slight to medium jerk when slowing down. This problem is caused by degraded/worn out mechatronics solenoids. I had this infamous gear slam when my mileage was only 58k km. Solution to this is replacement of 7 pieces solenoid, 7 litres of ZF ATF oil, AFT oil pan cum filter and labor charges which should be no more than RM3K.
Other than the above, ZF6HP19 is a reliable auto gearbox and recommended to replace the AFT fluid & filter every 50k km.
4. I heard from foreman claiming that BMW famous with oil leaking from all over the hoses connection and gasket-
The foreman could be referring to the older models i.e. E39 (5 series), E46 & E90 (3 series). He is right as the leaks are from the high pressure power steering hoses (E39) and the valve seals (E46 & E90 320i). BMW has rectified these issues for the E60.
5. Conclusion whether this will be a wise and better choice of my life time
A wise or better choice is always very subjective and only you yourself will be the best to make this call. E60 530i is a powerful car and the famous BMW straight 6 cylinders is smooth & stable cruising at 180 km and above. .