never have had a large fmic to know if it would fit or not. the stock pan is not flat. if your fmic is higher than the bottom of your bumper it should fit.
look at the picture above, the "B" pan is level with the bottom of the bumper.
hmm I can't see how it could mount any different. from the attachment of the wheel well liners to the bumper no other way to mount it.. Just that little "L" piece (spacer) that holds the pan low in that one area.
right now the car is having a head replaced. (now there is a modification I could have saved some money on.) so can't look again to verify. maybe I have a freak downpipe.