pretty much all TU engines will take all TU gearboxes, so yes itll fit
is it the 1.4xsi box or the 1.4 furio etc?
i have a 1.4xsi box on my 16v S1 and it is awesome, but my car is a track car (yet i do drive it daily)
what do you use your car for?
the normal advantage/disadvantage would be lower gear ratios but all depends on what you use it for