Porsche GT4 and GT3 compared

On a recent Roadrunner Region PCA drive out to Arizona I got the chance to drive a 991 GT3 on the same roads I was driving my 981 GT4, and I thought to share some notes on the back-to-back comparison my experience invited. This is not a detailed review of either car, just a comparison of how the cars drove. The cars are quite different in many respects, the placement of the engine being the most obvious, but there’s also the price ($150,000 verses $100,000). By the way, while the GT4 is a Porsche bargain—if a car costing six figures can ever be a bargain—you really do get more in a GT3 for the extra money you pay.


Before turning to the cars, let me describe the road. Ah, the road! Although we saw a lot more rocks, and generally dirtier conditions than we have seen in the past, Highway 191 in eastern Arizona is 90 miles of twisties between Clifton in the south and Alpine in the north. The twisties range from series of ten back to back tight curves, to sections of flowing curves, to a few straight sections. Most curves are unguarded, and the road’s edge is barely ten feet from the cliff’s edge. Many corners are blind, and in shadow. This year we were met by a few of the locals loitering around the corners: squirrels, cattle and calves, and even some feral pigs. It also rained…

Thanks to the kindness of my good friend Jim, we swapped cars for a twenty-mile section into Hannigan’s Meadow. I’d just got out of my manual-only GT4, and eagerly jumped into the PDKS-only GT3. Fortunately I’m familiar with PDK having enjoyed owning a Cayman GTS before swapping it for the GT4. But the PDKS in the GT3 is no ordinary PDK, with its deliberate, insanely fast shifts. Jim’s GT3 has the Sharkwerks X-pipe fitted, which adds another insane element—an insanely wonderful noise as the revs rise. There must be a flap that opens somewhere in the sports exhaust because around 5,000 rpm the note goes from fantastic to holy sh!t. While enjoying the PDK and the modified PSE, I got to form my initial reaction over the next few miles: this car is very different from the GT4!

The GT4 is a really great car. It deserves its position at the top of the 981 Boxster/Cayman lineup. It’s the car everyone wanted the Cayman to be, with its 3.8 liter normally aspirated engine out of the Carrera S in the right place, GT3 suspension and brakes, and an aero package to match its GT lineage. But just as the GT4 is a discrete step above the Cayman GTS, so the GT3 is as much, if not more, a step above the GT3. Back to back comparisons tend to exaggerate small differences, and these cars are similar in intent and execution. But the GT3 really does go to eleven! It is tighter, edgier, and more focused than the GT4.


Of course the GT3 is more powerful than the GT4, by almost 100hp, but that’s only 25% more than the GT4. The numbers belie the reality, as the delivery of those horses is alarmingly different. The GT3’s engine has more torque, and delivers early and often, all the way to its 9,000 rpm redline. The GT4 is a slow burner, and it’s not until you get above 4,000 rpm that it really starts cooking. With headers and an FVD tune my GT4 has nice mid-range grunt, and pulls hard out of corners, but while the GT4 takes its time getting to its 7800 rpm redline, the GT3 seems to spin easily and very quickly. The GT3’s gearing is shorter, and the pace is kept high thanks to millisecond shifts. Fortunately the manual shifter in the GT4 is sublime—perhaps the best manual shifter in any Porsche, ever—and upshifting is accomplished without any drama. Downshifts are assisted by the auto-blip feature if desired, or done with practiced heal-and-toe by switching out of Sport mode. Staying out of Sport mode keeps engine temperatures a little high, unfortunately. I must admit to being totally indifferent between manual and PDK under these driving conditions. PDK would certainly lead to faster lap times for someone like me, but spirited open road driving is not at all like driving on a track. These roads are dirty, strewn with rocks and livestock, unpredictable, and very narrow. Oh, and often there’s someone sharing the 20ft of road, going the other way!

But the biggest difference between the two cars is in the handling, and the way the cars feel on these tight twisty, country roads. I’ll try to sum it up this way: driving the GT3 fast is a three-part action. You brake and set the car up for the curve, you turn the corner, then you blast your way out of the corner. It’s not quite as discrete as the description, but close. Of course the car does each of those three things amazingly well, and when tied together seamlessly makes for very fast and confident cornering. Although the front suspension is the same in both cars, it feels sharper and offers more feedback in the GT3. Corners in the GT4 are taken more as one move, and the car sweeps rather than rotates. The GT4 maintains momentum, and transitions from braking, to turning, to accelerating more smoothly. I set the GT3 to standard PASM, while I ran the GT4 on Sport PASM, which seemed to give about the same feel, although the GT3 was providing more feedback, but at the price of feeling unsettled in the rough and undulating corners. (Why do these mountain roads always seem to have a dip right at the apex of the corner?)

During my time in both cars the same driver followed me, and he thought I was driving faster in the GT4. Since the GT3 was not my car, it’s possible I was unconsciously holding back, but I felt very comfortable and confident in the car at all times. Both cars had exactly the same seats, (and, by the way, very similar interiors, with lots of dark Alcantara and leather,) but I felt more forces in the GT3, I noticed in particular that my thigh muscles were working harder to keep me located in the seat, and I felt like I was going much faster in the GT3. The entire GT3 experience is more intense, more “raw”, and even though I had to work a little harder, ultimately more rewarding. When I returned to driving my GT4, I felt a little disappointed. While the GT4 goes to 10, the GT3 goes to 11.