Have you guys noticed this shift they're talking about ? I definately have. The first time it happened I thought the tires broke loose but I wasn't near the limit. There's an off-ramp on my way home that it happens on everytime.

When we first drove the 997 in Summer of 2004, we noticed one minor handling woe in two PASM-equipped test cars. Turning into sweeping bends, the seat of our pants gave both Editor Stout and I the feeling that the tires were gripping well but that the body was moving laterally on its rear bushings. It didn't threaten to do anything untoward, but it was the kind of subtle, unsettling glitch that shakes your confidence a bit. This small but undesirable characteristic showed up on most 993s, which introduced a rear subframe to the 911. Subsequent time with 997s - both in the U.S. and Europe - has confirmed our initial concern. Worse yet, several friends of the magazine with 996s, GT2s, and GT3s have noticed it in 997s, too.

It's an interesting quandary, because the 997 uses the same basic rear suspension design as the 996 - a series of 911s that didn't exhibit this trait. And neither does a steel-suspended 997 Carrera without PASM. No reputable scientist would dream of putting forward a theory without all the facts on the table. And, as we hadn't yet driven a 997 with Sport suspension, we wanted to do this before taking the argument a step further.

Speaking of PASM, Sport suspension, and the 997 Carrera S, we need to clear the air on another issue that's become well and truly mangled. Porsche says its 3.8-liter Carrera S with Sport suspension is capable of a 7-minute, 59-second lap of the Nürburgring with Walter Röhrl at the wheel. The base 3.6-liter 997 Carrera will turn an 8-minute, 15-second lap. When Porsche announced its Cayman S could do an 8-minute, 11-second lap, many publications - either not having read the press release fully or choosing to ignore the facts - shouted from the rooftops that the Cayman S is faster than the 997.

The press release went on to say that the Carrera was a totally basic, 3.6-liter model with standard suspension and steel brakes. The Cayman S had every possible advantage, thanks to optional PASM suspension and PCCB brakes. In the same way, we're not about to draw any final conclusions about 997 suspension without doing a back-to-back comparison of every permutation.

The day before, we had a fast run up and down some familiar roads in a red PASM-equipped C4S. Knowing what we were looking for, we soon established that whatever adjustments or changes Porsche has made to the 997 C4S have not changed the perceived lateral slack in the rear-end. It still shifts slightly mid-corner. It's a subtle thing, but it's there.

We would find one more piece of the puzzle thanks to Porsche's promise to provide us with a Sport suspension-equipped C4S test car in Monaco. During an in-depth conversation with chassis guru Georg Wahl after dinner, we gleaned some useful leads. He was intrigued by our criticism, to the point that he told us he would drive PASM and Sport suspension-equipped 997s back-to-back himself and let us know his own findings. Keen to get to the bottom of our question, he asked what speed we felt this effect - and whether we thought it was the weight of the engine moving on its own support bushings or a jacking effect rather than a pure lateral shift of the car on its suspension bushings.

To the first question, we replied that it can be felt at normal/fast road speeds, far from the limit. And, as there is no change from the 996 in engine mounts, it could not be that. After driving the Sport suspension-equipped C4S, however, a third line of thinking becomes obvious. It's the first time we've driven a 997 with the factory Sport suspension. Sitting lower and with conventional gas dampers in place of the electronic PASM units, the ride is a touch on the firm side - closer to a 2004 GT3's. That will suit the hardcore enthusiasts and track-day addicts this option is aimed at just fine, but, oddly, we feel the Sport suspension is actually less stiff at the rear end and offers a better balance between ride and handling than PASM-equipped 997s in Sport mode!

Interestingly, it also exhibits almost no trace of the lateral movement at the rear of the PASM-equipped 997. By a logical elimination of factors, we must conclude - for now, at least - that the perceived effect is an unintended by-product of the PASM system. It would be interesting to watch PASM and Sport suspension 997s go through a given corner at the same speed. Having watched Active Body Control-equipped Mercedes SL55 AMGs circulate Hockenheim at the Tuner Grand Prix, we've noticed that they try to self-level when exiting corners under power, causing some curious - to watch, from the outside - jacking effects.