Upgrade dilemma regarding a MacBook Pro mid 2012

I got this old MacBook Pro for free a couple of years ago, even though I upgraded it right away with more RAM and new battery. I also removed the optical drive for another internal SSD.

I really like this computer, it has served me well, The last week or so I've been thinking more of that 2015 refurbished MacBook Pro. So I came to a solution, I will make open last push for old one. my plan was replace the thermal paste at the CPU and GPU, as well get a set of quality fans.

Have anyone you guys tried this? Or read about someone tried?