Some questions before purchasing the XPS 9570

Hello everyone !　

First I would like to prevent you that English is not my mother tongue, so I'm sorry in advance for all the misspellings I will do

As it is written in the title my considering to buy the new 15inch model of the XPS line.
But I would like to know some stuff before doing it.
The model I'm interesting in is the i7, 16gb ram, 4K. I thought that it was the perfect match for note taking (so i will bring it with me at college) and light gaming. And I can buy it for 1650 euros because of the student discount.
I know it isn't a gaming laptop, but I don't want to play at 4K and ultra resolution with 150 fps, 1080p with high/medium resolution and 50~60 fps is far enough.

So what is my question ? Simply, Do you think that it is possible to have these performance ?
Especially if I:
- Undervolt
- Repaste (even if it is the first time that I will open a laptop) t
- Put new pads on the mosfet
and use a case with some feets to elevate it while gaming.

I have read this thread and I'm thinking of following it step by step: https://www.reddit.com/r/Dell/comments/7orxcs/how_to_get_your_xps_15_running_cold/

And I'm expecting these kind of performance:

What do you think about it ? I have only seven days for return it so I need to be sure, and I'm afraid to put all of this money without having what want.

Sorry for the long post, I hope you will understand my need and I wish you a great day !

 

I wish some XPS owner could comment on this, I am interested too.