Which is better and why? what brand?

 

If I ever decide to actually purchase one, it'll be a Flex-A-Lite or B&M. They are two good brands that get used by racers often. If they work on race cars, I'm sure they'll suffice on a Neon.

 

Thinking of getting the B&M 70268. Overkill? I hear stacked plate is better.

 

I've heard the smallest ones will work (which to me says go one size up). If you go too big, the fluid may not warm up and can start to sludge. They do sell thermostats for them though to prevent that in case you want one a bit bigger.

As for stacked plates being better, it's personal preference. Those, like everything, have their pros and cons. I doubt the factory piece is a stacked plate unit.