There are many different varieties of these changes but I use the Run N' Gun PB and here are my changes
1. Move Muhsin Muhammad to the #3 spot as a slot reciever. He is tall and a good route runner
2. Move Bernard Berrian to the #1 spot. He is fast and can do a spec catch
3. Move Bradley or Davis to the #2 spot. Davis is fast and can jump high. Bradley is fast (not as fast as Davis) and has good hands
4. OPTIONAL (I dont use this but yopu can if you want. mostly use this if you plan on passing more than running): Place Garrett Wolfe in the #1 RB position. Move Cedric Benson to the FB position. This makes the FB dives even more effective and has a faster and better recieving player at FB. This also makes your streches, screens, and passing plays better with Wolfe since he is fast, elusive, and has very good hands
Good Luck all you Bears players!