Experimenting with different gear choices can also help you gain some time. If you are debating on which gear to use when cornering in the wet the taller gear is likely the better choice if you are still following the dry line. The bigger gear allows you to mash the gas pedal a bit earlier without the worry of being in your engine's peak power band and it getting the better of you. Driving the wet line this may not be the case. Even with the need to make the ensuing added up shift on the following straight the lower gear is typically more beneficial. I have experimented with race rains and in addition to offering a super sticky soft rubber compound the tires that I used were a bit smaller in diameter than my Michelin dry's. That effectively changed my gearing so that my car was at a higher rpm at any given speed. So far I have found this is usually advantageous, it's like changing the ring and pinion so that the car's gearing is better suited for the wet. Driving the rain line typically means that you do more of the turning in the early portion of the corner and follow a straighter path past the apex to track out. At the slower mid corner speeds the shorter gearing allows me to keep the car in the engine's peak power band and have better acceleration.
There are some universal basics that should always be mentioned in any discussion on rain. Start with your tires close to their ideal hot pressures and bleed off some air if need be after a few laps. Stay off of the painted surfaces, even apex turtles, since they are all slippery. Don't ask a lot of the car when it's on concrete it's also slicker than the asphalt when wet. Although the fastest way around the track is often not the dry line most of the same principals still apply, especially the need to be smooth and to fully track out. If you are applying more gas you need to be unwinding the wheel. Common areas where cars go off the track in the dry are worn and may be small ponds of mud in the wet. Rivers can and do appear in the middle of a session. Learn where they come from and check their origin as you pass them to determine if they are likely to be a problem for you by the time you return on your next lap. If you can't avoid the puddles, hit them in a straight line. If the track is open but there is so much standing water that hydroplaning is unavoidable pit out. Just because control has not called the session doesn't mean that the conditions are safe for you, you've got to judge that yourself. Unless the rain is so heavy that the traffic has no effect on the conditions the ideal rain line is usually a bit of a moving target. Some mid session experimentation and adaptation usually reaps rewards. If conditions improve, and a partially dry line begins to appear, keep the loaded portion of the car at least a foot within the dry zone in case you slide a bit more than you anticipated. If you are slow and smooth with your inputs you are less likely to overreact when something needs a correction and cause a spin. With a loss of control the adage "both feet in" still applies, but I would advocate that a good fight be made first. As long as you are sliding on the pavement you still have some chance of slowing down. Once the friction of the paved surface disappears so does the braking and g forces that your body had been experiencing. That's why you may hear people falsely claim that they "accelerated" when they hit the wet grass.
Even though I consider my rain skills to be pretty good I always have some nervous energy when I get ready to enter a wet track. A bit of fear is a healthy thing as it sharpens your senses. If it were completely safe it would be pretty boring wouldn't it? How much of this applies to your 911, and whether all of this is wet weather specific for you, depends on how you like to drive and your car's set up. For the past 5 years Kristin and I have had pretty much the same suspension, this year we stiffened things up and will be back in the learning curve of how to drive what we now have. Wish us luck and if you see me heading out in the wet, and enjoyed reading this, please feel free to Rain-X the windshield for me. For some in-car video check the You Tube footage my friend Mike Kenny posted of me filling the car with water at Tremblant's German Challenge 2006.