@StubbedToe 

Here is the list of most compatible units for addition to X73-DSL:

X50, X55 and X60 - same form factor among these three, all are close in specs and performance. All three may not be available in all regions, or not sold in single units. Choose from these three models by availability and price.

X10 and X20 - these two are on budget side of compatible Deco models. May not have as good WiFi performance as X50/55/60, but should be better in price and could be just enough in performance.

X50-POE - choose this one if you need Deco unit to be wall or ceiling mounted indoors. This is the only one that can let you to, out of the box. Also, good choice if you want Deco unit to better blend with environment - you can put it on a desk or table and it will not stick out like X10-X60.

X50-Outdoor - choose this one if you need outdoor mounted Deco unit, for example to provide good WiFi coverage to front or back yard.

  @Alexandre. 

Thank you very much for the detailed explanation, it is extremely helpful and very much appreciated.

Regards,

Troy.