Could you in theory take apart a founders addition 5090 and add water cooling to it yourself instead of buying a 3rd party version

I'm asking because I'm planning on getting a 5090, but I don't want to spend an extra $400 on a water cooled version if I end up never using its extra features. However if I get a founders addition and realize at some point in the future that I want to push it harder, do I need to sell it and get a 3rd party version, or can I take it apart and add water cooling to it myself?