perdana spare parts are very easy to source, and are not expensive.
only problem is during timing belt change (not quite a big problem) because it has two belts (one for timing belt, one for balancing shaft). and the price of the timing belt kit cost around rm3++.
the most common problem is the water pump pipe "reput" or decay due to rust. the water pump pipe cost rm50, workmanship depends on your mechanic.
generally ownership of perdana will not cause headache. even if u change engine oil once a year (what i did). my engine mileage is 3++k km and only created engine-related problem once. the water pump pipe decayed, didnt notice temperature skyrocketed, overheated and had to do top overhaul + skim head. after that, it still went on serving its master. :)
oh yeah, before i forget, one more problem, the auto gearbox will fail. better buy a spare gearbox and keep. when the autobox breaks down, u dont have to go up and down looking for a replacement.
good luck on your perdana ownership!