Depends... if you have a GT you can either swap in a GTX fairly easily or just turbo the stock engine. IF you have a LX then the Zetec like was mentioned is a better option. Of course the 1.9CVH has a lot of potential that people don't really give it credit for. its not as easy as the BP (stock 91-96 GT engine) but it is still there.
concerning the CVH: you have to treat it like almost any other engine. it requires more milling work etc. but if you upgrade the components like cams, pistons, rods etc you can crank it up just like any V8 etc. The BP is blessed with really high quality stuff to begin with. that is why it is so easy to turbo etc.
No the BP motor we are reffering to is the Mazda BP engine. You can find it in the 323 (in turbo trim), protege, etc. It is a true mazda design. The 2gen Escorts were designed by both Ford and Mazda. It is essentially the Mazda BG chassis with a different body.
The CVH and Zetec are real ford engines... as far as I know.
Not 100% sure on this but I think the 97 2.0 that swaps into the 2nd Gen LX has to be a SPI not a Zetec. The 2.0 SPIs are relatively inexpensive and if you want one just let me know; I know of a place that has them for pretty cheep if you are on the West coast.