yes better go directly to Denso if your car has aircond issue. recently only i kena from 1 workshop in Tmn Len Seng, Cheras and wasted rm1400+ for their so call expert service.
First went there cause my aircond is blowing hot air. they plug in the meter & told me that the gas was low. After topping up the gas they said the compressor is not working so good & recommend to change the
compressor together with the condenser as well. after the gas refilled the aircond is back to working condition and guess what happened after 2 weeks? strong gas smell inside the car cabin & aircond was blowing warm air. Brought my car back to the same workshop & they said the cooling coil was leaking & need changing. they also asked to change the compressor magnetic coil since they said the compressor is not working good.
ok, fine trusted them. guess what happened again after 1 month? the compressor finally worn out. brought car back to consult them why so fast the compressor spoilt after changing the magnetic coil and now they said it has nothing to do with the coil & said its the compressor inside component spoilt. i said you guys should told me earlier to change the whole unit compressor but instead assured me that changing the magnetic coil was enough.they don't want to take any responsibility and claimed what they did is correct.
so guys, long story but a lesson learnt with my hard earned money. watever it is, make sure you go back to your sc or direct to Denso for aircond issue. oh yes, 1 more need to add to this story of mine. before sent to that workshop the aircond blower ( inside cabin) was working good. after took my car from the workshop the sound from the aircond blower was like a fighter jet ready to take off. guess what they workshop said? boss, we did nothing, we only took it out blew the dust using the compressed air. same thing, they won't admit its their wrong. 
fyi, the location of the shop is same row with sportstoto. next to them is a car spray paint shop & exhaust shop. please pm if you need to know the exact shop name but its not too difficult to identify since only 1 row of old shop at Tmn Len Seng Cheras.

edited the exact location of the shop.

Cooling coil if not mistaken located in the dasbord no? So much work need to be done, most of the time that the last thing they change .

an update to my earlier post:
solved my aircond compressor problem by changing to a New Denso compressor, New Denso condenser, New Denso blower motor. luckily went to this aircond shop in Tmn Maluri, Cheras (recommended by a friend) early before the compressor got worst. after the shop sifu dismantled the spoilt compressor he noticed got some light contamination only. he advised to replaced the condenser as well. he also did a thorough flushing of the system before installing the new compressor & condenser.
as for the noise of the aircond blower inside the cabin, he separated the fin from the motor and saw water mark & rust in the motor. he suspected that the previous shop dipped the whole unit inside water to washed the fin. please refer to the photo for better understanding.
for those who need a trustworthy shop to check the aircond, do pm me. not only i found he is honest but he did a good job. the previous shop has also spoilt the sponge which function to direct the outside air to blow at the condenser. he helped to custom made for me for free. while he was installing back the new blower motor to the car, he saw the casing which house the cooling coil is dusty. he said the previous shop did not even bother to wash away the dust since they opened it to changed the cooling coil earlier.
finally, thumbs up. 

I use myvi for 8 year already never experience like urs...i just do the full service on the aircond RM 350..but the mechanic said to me luckily my compressor not a problem...

myvi aircond compressor normal driving usually can tahan for 8-10yrs before show sign of problem lah, most myvi owner i know say the same thing, my previous myvi kena ac compressor problem after 9yrs.

your 8yrs myvi ac compressor got loud whizzing sound (usually mechanic describe it as aeroplane sound) when you rev your engine or not? if yes, mean the ac compressor aging liao.....get it check, maybe need add oil and service only.

workshop mechanic advice me......try to avoid sudden high rev when driving to avoid stress on the ac compressor.

so how much the damage is? care to tell...   huhu...

tiba tiba banyak cerita tentang air cond p2 kong... sebelum takde yg komplain pun.....

cooling coil have to change? last time i change condenser and recon compressor only... less than 1 k..

My workshop quoted over 800 for China brand a/c compressor, receiver drier and gas for my Myvi.. without supplier warranty.. I'm okay with the price but is it normal to have no supplier warranty? Bit skeptical..