the 6 spped box was built for the 1.1fire engine and won't fit the 1.6 as it isn't a fire engine, also it probably wouldn't handle the power of the 1.6
theres not much point of it, it was only really made for the young people in italy for when they first pass cos there limited to 1.1, so they could still have a 'sporty 6 speed', i think it sold really well over there, but obviously sold poorly in the uk cos we dont have limits.
As previously said it was a different range of engines, however if you have a 1.2 or 1.4 fire engine then they will fit but they are standard in the mk2 punto sportings anyway.