[Raceboy]

I often wonder why people don't get tired of saying "if Porsche didn't do this or that, it's not needed" etc.

Every 2 valve engine that has spark plug anywhere than centered benefits from twin-plugging and especially turbocharged engines that are used on the streets (=with pump fuel). Why? Because twin-plugging moves the MBT closer to TDC and hence reduces the detonation possibility and gains more power both because you can reach MBT with less advance and because reduced engine loss of combustion counterworking to piston that moves up.
Porsche did not use it on it's turbocharged street engines because of ridiculously low CR, big AR turbine and crappy fuel management (CIS). Porsche's main goal (like evry other car manufacturers) is not to offer best product possible, but to offer a product that just-just performs and does it cheaply (both by production cost and low warranty case count). Also the power improvements you see over model years are not developed on the fly but are carefully calculated and implemented gradually because once you make an ultimate engine/car how do you proceed next? I know this because I work in the car industry as a quality specialist for years.

Regarding OP's engine, no engine component can withstand poor tune and twin-plugging costs next to nothing when you go EFI and direct ignition.
He doesn't need forged pistons, Carillo rods etc for street driven, efi'ed 911.

Things tend to go backwards in 911 crowd, they think about the efi as a last thing, but in reality when turbocharging is involved on 911, it should be first thing to think about. Get rid of CIS and non-programmable ignition, one gets much better power, control, driveability and reliablity.
This is not a folklore, I talk this from my own personal experience (and it is backed by many others in both air and watercooled world).