--> you'd have to get 3 FX5 to have the biopower of one 2262. Then they'd be even for bio. I don't call that "kick butt"...

2 FX5 are outgunned by one 2262.
You are forgetting about the flow rate advantage.

1800 GPH vs 500-700 GPH. 3 Fx5s would have about 1100-1300 GPH
MORE Flow rate. On a 180 Gallon tank, The 2262 @ 700 GPH will have 3.8 CPH, where 3 Fx5s will have 10 CPH.
No doubt, 3 Fx5s would kill the 2262 at both mechanical and Biological.
Now, if you want to talk about 2 2262s and vs Fx5s...well... yikes... 6 Fx5s? Space? Although, 6 Fx5s = 3600 GPH. 2 2262s = 1000-1400 GPH
Once you achieve good mechanical filtration (which should be just fine with the flow rate of one of these guys),
This highly depends on the size of the aquarium. 700GPH should be fine, but most people with large tanks are using flow rates over 1000 GPH for mechanical reasons. Some for Both bio and mech.
increasing turnover doesn't do any good unless you house fish from fast-flowing streams.
This HIGHLY depends on the output position and type as well as tank size. Increasing flow rate WILL perform better where its needed.
Look at Eheim's track record - large canisters with low flow rate. They've been making canister filters since 1963. If you don't trust their experience then I don't know whom you'd trust ...
I forgot about that. The Comparison between the two filters (2080 and Fx5), you can't know for sure if its the flow rate, the media capacity or both. Without performing tests, you just can't say.
Lastly, feel free to search this forum for FX5 and Eheim Classics. You will find some user errors for the Eheims, but you will find several reports of equipment failure (though tolerant customer service) for the FX5. And the latter only have been out for a few years. Now who kicks whose butt
Where did this come from? I was simply stating for MEchanical and Bio purposes. I never once said the Fx5 would last as long or longer than the 2262.