tigras have adifferent loom connector at the engine from the early plastic manifolded lumps, but the same as the later ones, the early one also ran a air flow meter but i dont think the late ones did, the later ones also have egr and different head ports and are slightly less tuneable best off getting a whole engine and loom and ecu, then you cant go wrong
The C16XE fitted to early Corsa GSi's - has an airflow meter, larger inlets, very little/nothing in the way of emissions crap, and makes around 109BHP
The X16XE was fitted to late Corsa GSi's and all Sports. Smaller inlets than the 'C'. Slightly different head. Uses MAP instead of an airflow meter and has a fair bit of emissions junk. Makes 106BHP
The X16XEL was fitted to Astra's and Vectra's and .. ???? Mechanically its virtually the same as the X16XE but produces only 100BHP but the same amount of torque but its peak torque is lower down the rev range.
If you are replacing a X16 with a C16 then you must get the ECU and loom to go with it as region17rc says. Other than that, its a straight swap, both use the same block etc etc