Well adding any of these coolers will void the warranty guaranteed, I would honestly start by just making sure your case has good air flow.
I think some assemblers let you remove the cooler without voiding the warranty, mainly to let you change the thermal paste.
In addition to air flow, you can customize the fans curve. Probably the fans won't go to the 100% until 90ºC, so you can change it with MSI Afterburner to go faster (like 100% at 80ºC). You can try undervolting (but in my experience I have barely noticed improvements) but anyway if ultimately you need another solution like changing the cooling, first you should try to reapply thermal paste, a good one like Noctua NT-H1. Anyway that temps feel kinda high for that concrete graphics card so it can be a lack of thermal paste from factory.