I still have yet to watch TOS so if this is a big part of TOS please just answer this saying that, and no spoilers! 
In the 4th season of Enterprise it went to the alternate universe similar to the DS9 alternate 'verse. To me this seemed like a completely random event. It in no way had anything to do with all other episodes. What was the purpose of these two episodes?
Also why did they change the song to be a country/hip/whatever remix of Faith of the Heart? I thought it was perfectly fine in 1&2 once I got used to it being an actual song.

In the 4th season of Enterprise it went to the alternate universe similar to the DS9 alternate 'verse. To me this seemed like a completely random event. It in no way had anything to do with all other episodes. What was the purpose of these two episodes?
Also why did they change the song to be a country/hip/whatever remix of Faith of the Heart? I thought it was perfectly fine in 1&2 once I got used to it being an actual song.