Engine Swapping a fiat 127 with a 2006 Mini copper S Engine?

Or how about a modern-day Fiat/Abarth 1.4 T-Jet or Multiair? They're good for 120-250bhp using stock internals (depending on whether or not a turbo is fitted, and the type/mapping), with very impressive power and torque for their size. They are based on the old Fiat FIRE engines, so should slip into a Fiat 127 fairly easily. I know of one guy who fitted a Multiair into a Fiat Uno turbo, for instance.

I'm currently enjoying one in a 2008 Abarth Grande Punto. Goes well, and makes nice noises.

If they are DI engines you'll need to:

-Either figure out a way of making the stock ECU work and keeping it happy in a minimally trimmed form ; This would probably still be cheaper than any other option
-Pay out for either a DI Injector driver to work with an off-the-shelf standalone ECU, where I think even then you need to be careful what you choose or a DI based ECU ; Emerald is rumoured to do one but I've found no evidence to suggest this; Pectel do but it's super expensive. When I last checked, either route was north of £3k for simply an ECU. DI Injectors IIRC need a 48V supply. They have come down alot in price but still not to the levels of what us mere mortals pay for a 'branded' standalone ECU on a normally injected car.

If an engine from the earlier 1.4Ts, that may not be a bad shout for the aforementioned reasons you stated.

Of course, if they are not, it changes the scope quite alot and simplifies it.

The Ford Sigma 1.6 would get my vote here. They're light and the 1.6 can kick out around 120BHP with very little work. Duratec HE 1.8/2.0s are superb units but they are on the tall side even for MkII Escorts.

How about an Alfa 1.6 Twin Spark?

Has 120bhp, would suit the character of the car, there are plenty around and it's not overly complicated. No idea if it would fit however...