Suzuka
Ok here's my view of the circuit and what you need to tame it.
First you should drive the circuit in a slow car and soak in everything. Notice the main straight is down hill. The 'Ss' are up hill. The run off areas. There are only three. Turn 1, the 'spoon section, and the high speed R134 corner.
The first corner of any race is always crucial, but not the end of your racing day. Pole position will line up on the outside along with grid positions 3,5,7,etc. You have an advantage. You have the runoff area to use if a bottleneck develops at the start. Use it or risk getting bumped badly. Those of you in grid positions 2,4,6,etc. you are on the edge. You have nothing to escape the mayhem. Your survival hinges on getting to the corner and establishing a line with all four tires on the track. Don't even attempt trying to ride the inside curbs. Those behind you will try to squeeze a pass around you which will end up forcing you into the grass.
The 'S section. Learn it and understand it. It is uphill. Patience through it is your friend. If the car in front shuts the door, respect it. Choose another section to make your move.
The section leading to the bridge can be tricky with a sand trap waiting for you.
The hair pin. You want to hit this corner perfectly. Because the next sections will be all about speed.
The Spoon. It has a runoff area. Use it. Straddling the short strip of grass between the track and the runoff is asking for trouble.
R134. Get it right and you carry your speed to the final chicane. Get it wrong and the runoff area is your safety net.
The final chicane. A tight S which should be labeled 'short cut' penalty.
That's a brief summary of the track. I'll leave it up to you to find the other characteristics unique to Suzuka.
Cars. Pick the one you enjoy driving. I'll either be driving a Lexus 430 or a GT-R. Each car will have it's own strengths and weaknesses. Each car can be tuned in a variety of HP/Torque configurations. Power to weight ratios range in the low .90s.
Transmission, transmission, transmission. I can not say it enough. The gears you choose will decide everything. There are numerous gear tuning methods out there. Use each one and test. They're great. However, Suzuka is a different track so some gear ratios will need to be individually tuned. The Ss section is uphill. Yes GT6 will model you car going up hill. Don't lug the engine down. You need to watch your HP/Torque curve and tweak your gears accordingly. Use the data logger. Its amazing what it will reveal.
Manual vs Automatic. Both have their advantages and disadvantages. After 50 laps the real manual drivers will reveal themselves. I'll be using an automatic tuned to shift like a manual. Sorry that info is still classified.
Fuel will play a part. You need to know how much a splash and dash is.
If we were running teams it is possible to run 50 laps on one tank of fuel.
Tires. Always a factor in every race. If you screw up your settings the Ss will tell you. Front tires will take more punishment than the backs.
Down force. You will need it. So test with both low and medium settings and watch your SECTOR times.
Don't concentrate your tuning on overall lap times. Suzuka demands a balanced approach. You can not tune for the high speed sections and ignore the slower sections.
Braking points. Huh, as the race progresses your braking points will change. So don't concentrate on the young lady in the stands with the two large..... Big Gulps. She may not be there next lap around. They need to be refilled.
Engine health will also play a part in your overall race strategy. All of us lost HP after only an hour of racing at Lemans. Suzuka is no different.
Pit stops. Use them to gain an advantage. If you find yourself behind a slower car, pit and open up a clean track in front of you. My team will call me in three times. The pit window(s) is classified.
Ok, enough of me talking. If you need some experience and cash. Go to the International A races, scroll down to the Group GT 3 races. Suzuka is the last race. At 200% log in and five laps to win you should get a good idea what your doing right and wrong. Then compare yourself online AND USE THE DATA LOGGER
You may want to print this out.