the pulley you should be able to get from straight from eaton (that's who makes the supercharger not merc themselves) although i'm not sure which model it is, e90 springs to mind so you should consult them, as for the intercooler, the cheaper option that buying a specific kit is to make a kit yourself, you can buy good quality universal air to air intercoolers for cars for realtively little money, for problem is you have to make them fit, so the best thing to do it to see how your current one fits, and then measure how much space you have to work with, then you have to see about the pipework... and most importantly after all that, get a custom remap to make everything work the way it should