HarleyTechTalk

  Is a radio from a 06 interchangeable using it in an 05. Is it just a plug and play.   

Yes

Yes.. and no.  The radio will work minus AVC. The Ultra connector will not.

  Just to make this more clearer the 06 radio going to go in a 05 SE EG. Are the speakers going to be OK with the 06 radio. Thank You for the help and saving me time.

The speakers will be ok but it won't get as loud as it would with speakers that match the newer head unit.

 The radio that's in there is 46202-04a which is stock for that bike. It has 2 plugs with 23 pins. The 06 has a 23 and 35 pins. # 76160-06.

Like I said,  the ultra features won't work.

   My bad I miss that part.