ive seen both (got yours as a spare) but the only diffrence ive seen between them is the focus ib5 is cable oprated from the front of the box and the fiesta ib5 is rod oprated from the bottom rear of the box. So it would take abit of work fitting a fiesta ib5 into a focus.

im gussing you mean will the diff out of the rs turbo fit into the focus ib5, well i really dont know im going to try my self some time in the furture as i belive it should but i dont know anyone thats done it to a cable box.

you can put over 200 though them.