In regards to the engine selection. They are all the same between the years, but you have to go with an OBD2 1996-2002 vehicle if you plan on using the stock ECM, and going with a turbo down the road.
The stock fuel pump will not support a boosted application. You would need to upgrade that for sure, and also add in an adjustable regulator. When you need a tune get in touch with FlyinRyan who is on this board and also has a website
www.frptuning.com
I have been running a turboed magnum in my Valiant, using a stock ECM for almost a year tuned by Ryan. He is the man.