I've gone back and forth on the issue of RWS myself over the years. Currently for the type of driving experience I really enjoy I'd say I'm mildly against, but it really depends on both the car and the mission.

I'm surprised to see Sport Auto's test suggesting without RWS could be slightly faster. I'm sure Porsche's internal numbers say otherwise, at least in most situations.

At higher speeds where spirited driving occurs RWS is designed mainly to save time in transitions by limiting the "slip angle" the car adopts. Tires 101: no tire generating G force is moving exactly with the road. Instead it's "slipping" slightly, often imperceptibly, so that it's either rotating at a different speed or in a different direction than the road it's rolling on. That's "slip angle", and in a car corning hard it can be in the range of a few degrees with modern low profile tires...



What does this mean? For the front if the tire's got a large slip-angle in a corner we call it understeer: we're turning the wheel but the car's not fully listening. In the rear we might call slip angle oversteer, though only if the rear's slipping more than the front (forcing us to unwind the wheel to prevent swapping ends). Just because the rear's not oversteering, however, doesn't mean the rear isn't slipping by some amount, in fact at speed it needs to slip for the car to turn.

How does a rear tire "slip" (ie point in a different direction than the road) if it's attached to the car? Simple: slip the entire car. And that's what you're doing when you go around a corner quickly even if you're unaware- the entire car has adopted a slight angle relative to the road. Picture a dirt-track oval racer being far less enthusiastic:


This is all well and good... at least until you need to change direction and go the other way. At that point the car's slip angle needs to switch from perhaps 4 degrees in on one direction to the identical amount in the other. And as you might expect with moving any 1.7 ton object this takes both time and care.

There is however a way to short-circuit this process of changing direction. Don't point the car in a different direction, point just the rear wheels. Pointing wheels takes virtually no time at all and accomplishes the same thing because the tires get the slip angle they need to achieve grip. Thus it's typically a good thing, enough so that Porsche has been doing it since the '60s when it first introduced the 911: they have carefully engineered a "toe-curve" into their cars so that as it rolls into a corner the rears steer inwards. In the late 80s they added the "Weissach axle" to the 964 to augment this with extra passive steering as the car leaned into the corner. Finally recently they introduced full active (powered) rear wheel steering on top of the other systems to point the wheels that much further towards the apex. Keep in mind that all of this wheel pointing only serve to reduce the drift angle the chassis itself adopts: less dirt track racer, more roller coaster on rails.

Therein lies the rub. If you've never raced on dirt I can highly recommend: it's a lot of fun. It's much like managing the very high slip-angles generated by early cars with skinny tires. The enjoyment comes not simply from the slip-angle itself but the process of controlling it: managing under-steer on turn-in then counter-steering to catch the rear on the knife's edge before the back comes around. Getting that rear drift angle just right becomes both instinctive and addicting; from 60s 911 through my 991 GT3 it's one of the things I like most about 911s. It's also exactly what rear wheel steering gives you less of. Even worse it interferes with those slip receptors deep in the seat of your pants that are listening to understand what the car's doing. If you're used to rear wheel drive cars and especially 911s they are expecting the rear to slip in quick corners. And they can get awfully confused/ disappointed when it doesn't.

I get why people like rear wheel steering. I'm certain it's faster, especially in the wet. In fact autocrossing my 991.2 GT3 with RWS I can tell you all the places my car outperforms my buddy's 997.2 GT3 RS. There's also no question it's easier... But take away the clock and there's also no question which I find more challenging, fun and rewarding: it's not the car with RWS. Would I feel comfortable pushing to the point where I could make the same easy distinction on public roads? Generally not in those cars- they are both awfully fast for that. Thus if I wasn't planning for the car to make its living near the limit the extra performance and margin of the RWS would certainly appeal- I'd certainly spec something like the Turbo in a street car role with RWS (if it wasn't standard). For a "fun" car, however, my gut tendency would be to spec without. That said wheelbase, tire type, tuning of each setup, etc make a big difference to this conclusion so I'd like to test the 992 specifically. And I haven't.