Hey guys I was just wondering if it could be possible to add a pedal to an existing pedal set.

Because my friend is lending/loaning me his MC2 steering wheel so I could use that but on my Birthday I may get a DFP.

Yes, you can, just use the accelerator, and leave the wheel on the floor, you can

Clarification, you don't add the extra pedal to your already existing pedal set, but you plug the extra wheel/pedal controller into a USB port and it is set up separately. You can use multiple controllers at the same time. You would have to remap everything, ie, my momo alone has buttons 1-10, but with the joystick shifter attached, the buttons are somewhere around the 30's.