I actually re-read this whole thread.
I am exhausted.
One thing I did not see [and may have missed] but instead of a Dyno, are there any recorded comparisons of
As the top end seems to be the weak spot for the stock tune, I think that would really show the difference between a stock tuned 4C and a Stage 1 and Stage 2.
I don't think it would be too difficult to gather this data.
I do disagree on the statement that removing the Cat on modern turbo cars does not add any significant power.
Turbo's are spun by the Exhaust Gases. The Cat is the biggest restriction on Exhaust gases in a turbo car.
On the Kappa platform, we have extensive documentation and proof that replacing the stock cat with a High Flow Cat from Solo Performance adds 20+Hp on a 2.0 Liter engine with no other mods.
As a result, on the Kappa platform, the 2 best HP increasing Mods are a new HF Cat and tune.
That takes the car from 225WHP to 285-295WHP
I know the 4C is a different beast, so my statement is from my experience that non 4C platforms Do in fact benefit greatly from a less restrictive Cat