simply have a good look through terms and conditions of sale. also have a look at same on manufacturers website (if there is one). additionaly, were there and seals etc on the case that said 'warrenty void if broken' etc?
personally, I think that what you have done, by itself, would not matter. a system unit is not a 'no user serviceable components inside' piece of kit. unless you had some sort of mis-hap that we dont know about. but it would be down to you to determine the compatability of the components. Also, do they already know about these upgrades?