Hi Lancelot,
I had recently bought one and here are my answers to some of your questions;
1. Do consider the main dealers such as Sapura Auto or if you have to Auto Bavaria (see my other post re AB). They have a good selection of vehicles and you get peace of mind when you buy from them. Recons are tempting esp with their variety and selection but due to the amt of electronics on the car, I sleep better knowing I got it from a main dealer.
2. If you buy from a main dealer, your service/maintainance is covered for 3 yrs or 60k km, whichever earlier (from year of initial registration if second hand). For subsequent services, I would still consider sending it back to the main dealers considering how much the car cost. I think its false economics to save RM500 on a car costing over RM300k.
3. No idea as I just got my car. Again with a main dealer, you are covered for a little while.
4. Same as above. A little too early to tell for me. I did search extensively on the net for issues before my purchase but I didnt find anything major (most issues cited were related to idrive, transmission on 545 and 550).
I am very happy with my 525 sports (hopefully will remain so for the years to come!). Engine is fantastically smooth. Handling is amazing. Suspension is firm but on the comfortable side. PDC is brilliant. iDrive isnt as difficult to use as many have made it to be. Gripes are slight lag in throttle response and initial launch from standstill, and the steering feels a little remote.
Good luck with your hunt!