GTM will give you the optional water bottle if you ask for it. Smaller, maybe 1/2 gallon size?
Only problem is trying to find a place for it.. In the battery compartment is not a bad idea, even if you don't relocate it but maybe just get a smaller battery. Will have to look into that too.
BTW took it for a quick drive last night so far so good. No fluttering issues, no CEL, etc.. The rush of air you hear is pretty sick though.