The pre-facelift cars with the facelift interiors are regarded by many as the most desirable 156's (GTA's aside of course) so don't be too hasty scraping it. The 2.0 JTS was used until the end of GT production so you might get lucky and find a nice low mileage engine out of a rear ended/t-boned GT, or get a rebuilt engine.
Some of the more knowledgeable people will probably point out why you can't, but could you buy a JTS engine that had a cam belt failure and rebuilt it with your presumably still serviceable head on it?
I've just come to accept I can have money or have I an Alfa, but not both. I suppose I could have a diesel Alfa, the JTD engine seems a lot less temperamental than the twinnie or JTS, but for me the revvy engine is my favourite aspect of the car. I should point out the above is a preference, not a statement of one engine being better that the other. I am categorically, 100%, not opening THAT can of worms.