Normal service for oil change, I would say it's similar to Japanese car. Oil change for fully synthetic can be done RM100+
Personally I'm using Shell Helix Ultra, same as what service center is using. You can get it online or from Tesco during promotion.

For spare part wise, after market parts are readily available. Pricing are very similar to Japanese rivals.

If you plan to go for original OEM parts, you'll be surprised that Korea original parts are much cheaper than Japanese original parts.
Besides, I can tell you that there are a lot of "fake" Honda and Toyota parts out there with fake original packaging. Not so much for Korean cars, maybe the demand is not that high, so no one are counterfeiting Korean spare parts yet 

Any workshop should be fine. You can Google around for Korean car specialist as well if you like. Korean car are very similar in design as compared with Japanese and local cars. Front wheel drive, McPherson struts, engine layout etc.

I have changed my absorber and engine mounting. I bought online and took it to normal workshop to replace it. They did it just fine