If you intend on fitting the 6 speed getrag box you will need ST170 shafts and hubs, then you will need the brakes also.
You will need the dash clocks and the interior loom, you will need the ST170 engine mounts as i belive the 1.6 has different mounts. The ST170 has a unique fuel pump controled by the ECU with no fuel return so you will need this along with the hoses and maybe tank too.
It is a parts swapping excersise, no cutting or welding involved etc just allot of parts to swap.

My ST170 does an average of 22mpg but i belive my bank one O2 sensor needs changing