if the cat is not fitted in the direction it should be then the cat will not flow at max flow ( roughly halved beleive it or not )!!!
So, now your cat is not really "HIGHFLOW" its junk
tell them to replace it.
It is fine, it will give a better idle...
Ask Dr.Drift ( SAM ) He does this to all his customers cars now after many years of using the AFM before the turbo he now preffer's it attached with the intercooler piping.
Whats wrong with dosing? it definately sounds better then a crappy poofter valve!
get a metal intake pipe made up! switch your airflow meter into the cooler pipe then get your car tuned ( assuming you have a power FC etc )
Good luck