Thanks for all the info. P4000 looks pretty good both by price and performance and I also have an external flasher with a clip so should be easy enough. Also, I see @TheQuentincc had 2133mhz RAM working with M6700. I tried flashing XMP with Thaiphoon but even when setting XMP timings to stock, laptop just refused to post and diagnostic leds weren't working either. I have I7-3940XM and 4x8GB DDR3L Hynix sticks so I wanted to OC them to at least 1866MHz.
I was also wondering if there's a chance for M6700 to use something more powerful than a 240W adapter (like a 330W Alienware adapter). I have read in forums before that the laptop recognizes a 330W adapter but refuses to use more than 240W. Was there ever found a workaround for that?
Edit: Yeah apparently i was looking at the desktop version of P4000 and was impressed how good it was until i realised it wasn't mobile one 😅. Yeah... prices on those on eBay are quite high for being little more powerful than Tesla M6 which i got for dirt cheap.