There is a supercharger from ESS for the E46 that can be modified to fit the E60.
Because you have the M54 hopes are there. N52 owners have nothing. Here's a
video with results. Note the 530i DESPERATELY needs an exhaust. It's like trying
to blow through a straw. Based on the runs it looks like it will easily pull on the stock
335 with the exhaust upgrade. Good Luck.