It really makes no sense at all to turbo the 1.4, firstly to cope with a turbo you would need a set of lower comp. ratio pistons, new (possibly one off fabricated) manifold, possibly an uprated crank, and a custom map on the ecu, oh and a turbo,then an engineers report for a modified car, and stupid insurance premiums ( a car modded to be 150bhp from 100 would be dearer to insure than a 150bhp model from the same range) the costs involved would be huge unless you had a reason to stick with that car, then your better getting a faster model from the off.
That being said if you chuck enough cash at it it would be possible, anything is if you have the cash to burn on it, but not viable