Wow. I thought most laptop now comes with locked BIOS so you can't do those undervolt stuff already. Good to know that software can be used
May I know what is your config for your Acer ? 4720HQ + gtx960m + 8gb ram + 1tb HDD ?
If your Acer is the old model, gtx860m + 4710HQ, your temperature is definitely too high. You're even in an air condition room. IIRC, in aircond room, your temperature will be <85 for gpu and cpu.
Do a benchmark. Do it for about 1 hours. See what temperature you get for your CPU and GPU. If it is stable it should be around 80-85 or even lesser.

P.S: You may consider other thermal paste like GC Extreme. I heard that it is better than IC Diamond.

It certainly will affect the battery life. But the effect is not as bad as heat. Heat is battery no.1 enemy. I suggest just unplug the charger whenever it reaches 100%. or even better just use the battery as u wish since sooner or later the battery will deteriorate anyway, thats the side effect of built in battery.

Different manufacturer different setting. Actually when i use v nitro before this i never use any cooler, since the fan is at the back theres no point of using cooler, just make sure that u lift up the back part a bit higher so that the air can easily flow. That would do the trick. U can try and see the difference in temperature when u lift and not lift the back. 

I cant remember correctly as i already sell the laptop    if im not misaken D2 under aircond room should be below 82C for both cpu n gpu in max settings.

Try after it is fully charged, switch off the power adapter and wait a few seconds. Then plug it back and switch on the adapter. The indicator of the battery will most probably be updated by that time

Oh btw guys, my fan starts running frequently while playing games after updated bios to latest version

Well, you can try to test the settings for yourself until it suits you. Or you can follow my setting in the previous post.

Wow that is some serious temp you've got. Not sure if mine will turn me down like this  Happy getting your z5 

bro, is it really that unsatisfied? cause i m planning to get 1..but it looks like got many problems..
do you play dota 2?will it be overheat when playing dota2?

ya bro, i knew your feel 
what is the temperature when u tested gta V at Pc image? i cant see it clearly... 90 +?

Wow u get a new sealed set?

Then have your issues been fix after replacing the heatsink?