I rented a  6616   a couple years ago..  pulled my  16 foot  disc mower in 9 foot tall sorghum,  and  baled  the hay behind it.  

I had no idea it was  a 4 cylinder until I popped the hood for a look-see!   It sure didn't  'sound' like one!

I was told it was  160 hp..  and   it ran that disc mower  with ease.    

It was my first experience with a DEF machine...  and  had to keep it  at least half full in my side hills-  the computer would  'see'  the def was getting low, and start flashing  'warnings'  
It had the cvt trans,  and  I have to admit,  I kinda liked traveling   30+ mph  heading home!

I didn't use it much into the Fall,  but could tell it was always eager to start on cool mornings.      You have to give the hydraulics a minute or 2 to warm up before you can even move the tractor.