I have not used routing components.
my advice is check yourself by checking rebuild time of these items in assembly. Rebuild time can be found through Assembly Visualization tool.
below is the link to a comprehensive article by Alin Vargatu
The question isn't if elbows, Tee's, concentric reducers, etc. if it affect system performance.
Of course it will, anything that is frequently used in the assembly will affect performance, even more so if it has configurations, which any normal routing component will have. On top of it routing will for a large part be determinid by external reference (distance from something, connected to something,etc) with supports and equipment that either dictate the route or the route dicating their locations.
There for the question is: what else would you use to depict the same thing without routing components that still gives your the benefit of using routing components?
PS.: Our core business with SW is the routing module, anywhere from skid kind of constructions to full installations.
The latest one my colleague is drawing/designing is a Biogas installation which has more then 10km of piping underground alone. We have had to devise a compartmentalized system so that no matter what we want to depict in the 3dmodel we can load only those pieces that we need for that particular area without having to wait 10 minutes.