(T) Power gains when CAT is removed

Does anybody know more or less what the power gain would be on the Abarth if the catalytic converters are removed? (i.e. replace the exhaust system with a free-flow model.) Somebody must have done this already...

Catalytic converters rob between 5 and 10 bhp depending on engine size, I would guess a decat on an abarth would be worth 10 bhp.

I have a Supersprint stainless steel cat back(from the downpipe) on mine & it's supposed to give 8bhp! There is more than one on the abarth BTW.

For a 10 bhp gain it might be worth while...
My idea is to have the whole exhaust system replaced with a custom stainless steel one. This would include replacing the exhaust manifold with branches. My idea is to get rid of all 3 CATs and then run the car with a higher octane fuel.
Removing the CATs also eliminates the dependancy of only being able to use unleaded fuel.

Supersprint do a downpipe/manifold as well although it is quite expensive but it goes together with the rest of the exhaust.