It depends on the year of the car. Up to around 2011/12 non MFSW cars were fitted with an SZL unit (steering wheel control unit - the part with the indicator stalks and angle sensor/clock spring) had the connectors but not the internal wiring so that might need changed. Only real way to tell is to put in a MFSW and see if the stereo controls work, if they do you are good, if not then it is an expensive and tedious job replacing the SZL. Either way, you will require programming/coding to get the cruise control to work but other than the SZL all the other parts and wiring are already prepared. Bear in mind that when you swap out steering wheels your angle sensor will probably be out so you will get the trifecta warning lights (ABS/brakes and DSC) coming on. Also remember to disconnect the negative battery connection before removing the airbag if you are going to try this. If you are going to replace the SZL you must get the correct one for your vehicle (get the part number from realoem.com), i.e rain sensors or not, etc. You can sometimes get lucky and find the correct one on fleabay if you are in the UK.
Cooper 2009, R57.