I think there is a chance that other radios can be easily wired to play through the BMW DSP system also. At least the non-NAV systems which is what I have experience with. There is another thread in the E53 forum that describes the install of an Advant-2 in a X5 with DSP. It's a simple solution and just requires connecting 3 wires (hot, ground and CANBus) to the Business Radio/Disc player. Just connecting these wires as described in the Installation Guide in not enough. You have to be sure that there is 12v. on the hot (red) connection to power the disc player and MID display. You can provide the 12v supply either by tapping into a positive (+) battery connection close to the disk player location or you can splice into the red wire in the connection to the MID display and connect that lead to one of the positive (+) connections coming out of the radio. This method avoids the possibility of parasitic power drains on your battery, because the MID is only powered up when the radio is turned on. With the Advant-2 I used a lead from the radio labeled "AMP On". With the Eonon, I used a lead that is labeled "ANT +" and is used to power the antenna motor if you have one. The key to getting the DSP to work with an upgraded radio is to be sure the MID is getting power (12v.). If it doesn't light up, check that there is 12v. on the red/blue wire on the MID connector.