how much HP can you really gain from a turbo and are thur dif kinds?

Horsepower is an imaginary number, based on torque.

So, forget horsepower.

You want torque.

Secondly, ur gains can be anything from -100, to +500.

Depending on turbo size, engine modifications, fuel, tuning, etc. Nevermind that there is roughly 1,000 different types & sizes of turbos.

As far as what is best?

NOT turboing the car. You'd need to change the pistons, rods, redo the bottom end of the block, etc, just to handle the power of a turbo, if u intend to actually get any gains out of it.

All said & done, u will spend several times more on ur car, than if u had bought a stock turbo vehicle.

And it will be slower than that stock turbo vehicle, as well.

The best one is the factory turbo that comes with the Dodge Neon RT4. If you must have a turbo neon, sell yours and buy a used RT4. Those small Chrysler engines are not too reliable to begin with, if you put a turbo on yours it will cost a lot of money and it will blow up. Good luck.

well u can gain 120 to like 500 hp but u dont need to turbo a neon its still not going to beat my v6 mustang just take good car of it & change air filters & resale it then by yourself a nice v6 car or v8 but shoot turbos will set u back like 5 grand u can buy a gt mustang for that almost & ur car hast to be in good shape before u can but a turbo on it but good luck but if u do put a turbo on it l recommand vorteck there pricey but comes with everything u need with an intercooler well good luck

Just swap a turbo engine from a PT cruiser :)