As mentioned wifi testing is extremely hard and even the professionals test environments can get misleading results. It all does not really matter since the most common issues with wifi tend to be the house itself and/or the end devices. You hear many people upgrade routers and see no change.
Testing ethernet is almost a waste of time. Even a very inexpensive router can do gigabit wan/lan. These device have offloaded the NAT function to hardware so the CPU does not impact the traffic. I suppose you could turn off the feature and test but then you would pretty much be testing cpu clock speeds more than anything else.