Sorta off topic but how fast are you guys going entering and mid drift through medium to large corners?
Grand Valley, turn 1, about 130-140mph
Naw, it's like Streeto said, it varies from corner to corner. I'm actually really bad at paying attention to my speedo, I just go by feel
Transmission is really important in drifting, especially to induce drifts. Make sure your 3rd and 4th gears are set up to kick in at really high rpm to induce wheelspin. 3rd and 4th is key.
Set the final so 3rd and 4th cover the speeds at which you like to drift. The other gears don't really matter so you can sacrifice them to make 3rd and 4th spin inducing, even with a fairly wide final gear ratio. Muscle cars are different however as they prefer low-mid range rpm.
Transmission tuning might look confusing but its really easy once you learn.
I agree that transmission tuning is very important, but disagree that "it's all about 3 & 4". It really depends how the car is built, and on dricer style. Input method (DS3 vs wheel) makes a huge difference as well. Cars with lots of torque, and/or cars that have wide power band can get away with using fewer gears, like you suggest - that said, it doesn't always need to be 3 and 4. I know some people who drift Corvettes at Suzuka and pretty much use 5 and 6 exclusively. On the other hand, I also know people who drift ISFs and M5s, and at the old D1 section at Tsukuba, they use all 7 gears available (5 or even 6 through the esses, down to 1 to help trail brake the car into the hairpin, 3/4 through the apex, then back up to 7 for the short straight before going back to 3/4/5 for the final right hander under the bridge).
People who use a wheel (and especially with the transmission issues related to wheels in GT6) tend to be able to use fewer gears, as they have more dexterity in feathering the throttle.
People who use controllers can get away with using more gears. A trick I learned a long time ago is to build very close ratio transmissions, and to use the transmission to actually help steer the car on entry and apex, and then use rapid upshifts to help control wheelspin to maximize acceleration out of the corner.
Most people don't realise how important a dialed-in suspension setup is for drifting and tandems. You don't even need a transmission tune if you have a proper suspension.... that in itself speaks highly about tuning. Some days I just pick a car add an LSD, minimal power and weight mods and a FC Suspension on Comfort Hards. That's my entire upgrade list. Oh and if you're wondering how effective a decent tune really is.. With half day's worth of tuning I can pull 20,000+ points on Tsuku all without breaking the bank on power mods.
I don't disagree with you at all, but just to point out, the same can be said vice versa, in refernce to the bold text. A car with a properly set up transmission and diff can get away with little to no suspension and power mods, the same way a properly set up suspension can get away with no transmission tuning. Obviously, to get the maximum out of the car, all aspects of tuning need to be considered.