If you add a Wii Remote to Remote Buddy, it has to scan for it on a regular basis as part of its support for that device, which leads to more Bluetooth traffic. This can lead to more packet collisions and have an impact on the performance of your WiFi.

Apple, in a knowledge base article on this subject (http://support.apple.com/en-us/HT1365) therefore suggests:

"Minimize the number of active Bluetooth wireless devices you have connected to the computer or operating in the area."

The easiest way to avoid interference between your Bluetooth devices and your WiFi network in the first place, however, is to delegate both to different bands: if your base station and Mac both support 5 GHz WiFi networks, setting them up to use the 5 GHz band will avoid this issue entirely.