bro, thanks for the info. after few weeks of observation, oil level still the same. then i started the engine, wait warming up and rev it until 6k rpm. can see a lot white smoke. how to confirm this is valve seals or piston rings problem?If Selangor, I would suggest you to try Haz Motorsports Garage near Salak Jaya (Salak Selatan). Did my overhaulin there and no problem so far. Plenty of 20valvers being transplanted and modded from this workshop.
Also, Kegani Autotech (Bandar Kinrara) is a good choice too. Just make sure you bring your cheque book ;)