How do I install it? Do I have to tap in to the radiator or somewhere else?

 

Tap it off the coolant temp sensor located on the left side of the motor. Your car already has a engine/coolant temp gauge, why do you want another one?

 

Probably because ours are weighted so minor variations don't make the needle move. Car manufacturers do that on purpose so people don't panic when the needle moves once the car reaches normal operating temperature. However, if you drag race, knowing the exact coolant temperture can be very helpful.

 

That's pretty much it. I read someone saying that their stock gauge reads normal and the aftermarket one with actual temperatures can differentiate ~40 degrees

 

It isn't that the factory gauges are that inaccurate but if the temperature swing is 20 degrees from normal when in heavy stop and go traffic on a hot day, the needle won't move to reflect that. An aftermarket gauge will show the actual temperature changes.

 

And to add to that I had radiator problems so now I'm sort of paranoid lol

 

You need a place to tap into. I fabbed up a water temp gauge adapter and cut the upper radiator hose. You may find one on ebay.