Acer ES1-131 / ES1-531 Warranty status on RAM Upgradation

Hi,
I have narrowed my choices down to these two laptops for purchase:
1. Acer ES 11 NX.MYKSI.021 ES1-131 (11.6, Celeron Dual Core,2GB RAM, 500GB HDD, Win 10 Home)
2. Acer E15 UN.MZ8SI.023 ES1-531-C2YE (15..6, Celeron Dual Core,2GB RAM, 500GB HDD, DOS)

The thing is I have a 4GB DDR3 (1.35V Low Voltage) RAM chip as a spare from a non-functioning laptop, so I would like to remove the default 2GB RAM and put this in its place (since both laptops have only one RAM slot). However, from what I have read/seen so far, the disassemby of both laptops is quite complicated for a novice, as the entire bottom has to be dismantled. Obviously, since I am buying this as a low cost option, I dont want to end up paying 25% or more of the price for just the installation of the RAM chip I already have. So, what I was wondering was - what would be the status of the warranty if I do manage to replace the RAM chip myself, or if I got it done by a local computer repair guy?? FYI, I am from Mumbai, India - in case the answer varies depending on the location.