Any concerns with stacking 400's

[Mikeeo]

Hello All,
Just sending off the cheque for a set of 400's...arriving in a few weeks.  Needless to say, very excited.  Are there concerns with stacking the units or is this the typical arrangement for most users?  
I note the ad copy often shows them one on top of the other.  If stacking is fine would one take precedence over the other?  Master on top...etc.  Will they overheat or is this the design intent? Thanks in advance.
Cheers,
Wdw

Hi,

I stacked mine from the beginning but due to space restraints. Changed equipment table and the placed them side by side and I noticed some deg C less for both units. Having them side by side gives the possibility to have footers for each unit which these units really need. I would recommend Ansuz Darkz feet, they make so much difference that their price will seem like a bargain despite their high cost. Guillaume can give good witness about these feet under his D800 units.

Best/Mike