Can anyone tell me if the MCS and MC front bumpers are interchangeable for the 2005 model year?

 

for the most part, yes. Fog lights are a little different in location, and on the rear bumper, the rear valance needs to be changed due to the exhaust outlet location. There is a slight difference in shape of the bumper to valance, but you will only really notice it if you look up close.

 

In 05 there was a facelift which changed the design of the Cooper front and rear bumper covers and several other things. The front is a direct bolt on provided that you changed the position of the foglights or inserts like stated above. However, the rear is totally different and you will have to get the early model (04 and back) lower trim pieces to make it work(the black wrap around pieces, 3 to be exact).