Got it in today. I will be doing some testing over the next few days -- here is a comparison to the 1500D v.2 model -- the new v.3 is longer to fit all of the new parts and the fan but is narrower.
The newer 2500D v.2 and 3500D v.2 will actually shrink in width AND length compared to the old units for reference.
* The fan blows through the board to expel air out the sides of the amp. Will do a heck of a job in terms of cooling