Amperages and duty cycles alone are arbitrary measures of a torches capability.
For a more accurate appreciation wire type, gas type, flow rate and open circuit voltage must all be taken into consideration. The XP8 is rated in Amps as a guideline but the Kilowattage requirement of a given application provides a far more accurate method for calculating torch selection.

Kilowattage represents the total power rating required and is calculated as follows:

(Amps x Volts = Watts , 1000 Watts = 1 kW)

The simple answer is yes. The use of different gas types can have a marked effect on the performance of air cooled torches. Generally the higher the content of CO2 in the shielding gas the better the performance of the Mig torch.