The 1.4 12v was only ever SPI.
Even though the 1.2 does have the same BHP the 1.4 has a faster 0-60 and more torque.
Ive been thinking about setting up MPI and a custom ECU (like Megasquirt) on my 1.4 if i ever get a bottom end to fix it.
Theres a lot of info about custom ECU's in the cinquecento section.