I think your best option is probably California. They have strict laws, but a lot of people don't listen and list a disclaimer on their products. The other thing is that you'll be within driving distance of Vegas which has a lot of money and also the SEMA show that is probably the biggest thing in car culture here in the states. At least on an organizational level. Also, the climate is going to allow you get good test data pretty much year round. No snow or days that are too cold and icy. Another thing is that Hyundai has a huge base in CA, might be able to get better access to info, parts etc just because you're down the street and from the old country. Just a thought.
Texas is probably 2nd best. Big state, flat, and not as strict. Lots of companies are relocating from CA to Texas or placing big operations there like Tesla.
But 1st, bring the mobil dyno to Massachusetts. My
G70 needs the tune that comes with extra gap sauce!