Friend
First and foremost I applaud you for examining this topic before wasting money overtime by going through different pieces. Separates are going to give you the edge during times you want to critically listen and/or turn the volume up. This will only be realized through direct comparison. If you listen at low volume most of the time - you can get away with a well built Integrated.
Both will sound great; but in my opinion separates are the way to go. Purchasing piece by piece is fine as funds permit. McIntosh makes great gear - so you will be fine there, but you will have to determine whether it will be Solid State or Vacuum Tubes.

