Yes and yes. Use the higher temp thermostat, since in our generally moderate and definitely humid environment, it helps the engine work more efficiently. It also helps drive off accumulated water from the oil, reducing sludging inside the engine.

And yes, it's right up top on the engine, right in front. One of the easiest things to get at actually. New thermostats will come with a new o-ring seal - there's no other gasket. Clean up the sealing surface and the water neck well before reinstalling. You will lose a bit of coolant, nothing much you can do except put a wide pan under it. If the factory splash pan is still in place, you can just put your pan under the back corners to catch the coolant as it drains out there. A big pile of old newspapers under the whole thing would be a great idea too, that'll prevent staining the driveway or sending any to the storm drains.

You don't need to remove the top radiator hose for this job, just the 2 10mm nuts and the lifting eye on the front of the engine. However, just go easy when folding back the hose. The plastic tanks and water nipples on the original radiators are very fragile. Don't flex the thing any more than necessary to remove the thermostat. And don't be surprised to find green, yellow, sticky, grey crud in the housing. Just clean it all up and observe orientation of the old thermostat when installing the new one.

Good luck!
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Rob Bareiss, New London CT ::: Roterande Fläkt Och Drivremmar!