Sounds silly to drop a 2.2L Lotus 4-banger into a Contour. Just leave the Contour alone and buy your Lotus.
I prefer to have 2 cars rather than one that I mod the heck out of.
3.0L Duratec is your best bet. Or you could downgrade to a Zetec and then try to turbo it!!

Remember you're going to have to figure out how to mate your transmission to the engine, so if you want difficult, then by all means, go for the Lotus engine.