Rotor-Sound77

Hey Guys
I am currently in the process of buying an Fc Rx7 S4 N/A that has been sitting for 26 Years.
I have checked the car out and the engine turns by hand. I think it will run again but I am making plans on rebuilding it at some point and want to go through my options in terms if porting.
I live in Germany and i want to be able to pass emissions with this motor. Thus i have to keep the stock intake and exhaust. Well at least for the test and after that i can put a propper exhaust on it.
Btw the early EU FCs have a thermal reactor. I will keep the stock intake manifold.
I want to make as much power as possible staying N/A and still pass emissions/stay under the radar with police if they ever pop my hood.

The Plan currently is to do a streetport, port the intake manifold and remove the diffusors in the exhaust with a small widening/transitioning of the exhaust port.
I have read alot about bridgeporting the 5/6 ports and it would work if i had enough flow for it.(i know it is a compromise staying with the modified yet stock manifold but it's all i can do with staying "legal")
EU-spec Manifolds don't have sleeves in the port. They have a butterfly valve in the Intake manifold just before the port. A bridgeport braps because it has overlap and it gets air out of the massive manifold runners.
The 5/6 ports are closed but there is still some plenum volume between the butterflyvalve and the aux bridge port opening.
Is this enough to make the car not idle under 1k rpm? I can't have the gnarly braps because of emissions 😑...

Will it brap? Can i get the Rpm low enough with some fuel/spark tuning?
The plan is to go aftermarket ECU or piggyback. I haven't looked into that very much.

Help is greatly appreciated!