Yea I don’t wanna break further haha
I’m thinking for 5.5k to spend which means I can opt for another 120 hz display or SSD upgrade. Only one, so in your opinion which wold you suggest me to go for

That's non aircond room right? My AW13 with less powerful i7-7700HQ is cooler than that without re-paste.

Got my Alienware 15 R4 with following spec for a week now. Thought wanted to give my experience with it.

i7-8750, GTX1070, 1TB SSD, 8GB 2400mhz, 1080p 60hz (G-Sync Enabled)

Build Quality
As expected, top of the line quality feel. Nice and sturdy, almost 0 keyboard flex and display panel flex. Keyboard is nice to type on. However the Alien Command Center is a bit buggy sometime when starting the computer (missing Home & FX  Tab form time to time). Had to close the ACC service and restart the Command Center. The track pad is nice and it lights up! Webcam was okay, although speaker is a bit distorted at high volume. not sure if wanted to call Dell to have a look at it. Battery life is around 2.5 hrs for my normal usage as the display is G-sync.

Gaming
The gaming experience is awesome. Didn't get to play many games. Played Dota 2 with max setting (Dx11), around 120 fps. Tomb Raider on 1080p max setting on the other hand is around max, 150fps, min 70fps and avg of 110 fps.

Thermal
This part is a bit disappointing. At first I didn't believe what they're saying in notebookreview forum. What they discussed is true. Playing Tomb Raider the system throttles on Core # 0, 2 & 4 with temp reach above 90 to even 100. While the other core are at 84 degree to 95 degree. Suspected an uneven heat sink to CPU die as mentioned by iunlock.
Running Dell Stress test result in same temperature with max clock of 3.992Ghz. Due to this temp, I contacted Dell yesterday (17/8/2018). They respond very quickly and will provide replacement parts (asked what part and they didn't reply) and wait for on site engineer to make an appointment. Bought myself Thermal grizzly Kryonaut to ask the engineer to use this instead. Edit: the replacement part is the heat sink.
Today i try undervolting the CPU using XTU. Undervolt to -0.05, Playing Tomb Raider the temperature barely hit 90 degree. Further undervolting to -0.100, resulting temp barely reaching 80 degree and  maintain clock speed of 3.992 GHz.
I did accidentally overvolted to +0.100 and ran Tomb Raider. Will this damage the CPU? The system throttles to 3.82 Ghz.

Note: I always rise the laptop to allow airflow.

While in subject of clock, Tried overclocking the display. only manage to overclock until 67Hz, any higher will cause black screen.

Overall
Like the laptop and will keep it. The thermal is the only issue with this laptop. Hope the on site engineer will be able to fix it with the new parts. planning to do LM in the future. For now, ill utilize the on site support that come with this laptop. Will re-pasting with LM void warranty?

Afraid to damage the CPU or reduce its lifespan.

Bought at Shopee for Rm29 (1g). Rm 33 after shipping.

One thing to add, the palm rest has nice rubbery texture. However, it attracts oily/wet palm and cause it to stain. you can wipe with damp cloth to remove it, but it'll show some traces of the wiped area (my sensitive eye). Recommend putting dbrand skin. I Plan to put one on my laptop as well.

How did you ask for the replacement unit?

D Brand have 15% sell on all skin. There's a new skin pattern as well.

did you try undervolt that beast though?

I bought cooler master u3 plus and 2 units 8inch mini fans to blow it while playing game ... 

FYI, I just upgrade BIOS from ver 1.1.6 to 1.5.0. Looks like it got little bit improvement for temperature control. 

[attachmentid=10034421]

Do update us over here on the progress!