That's IA-1 with the NSX-R?
I had bronze, after finishing careermode i tried again.
Took me 4 minutes for gold.( nice, i can check back on my youtube )
I used automatic gear.
used steeringhelp at "weak"
Traction 3
controller at 3 ( did it with DS3=gamepad and no thumbstick used)
play with the throttle, no brake needed.
You only speed up to gear 2 and don't go to fast, or the car breaks out more at every turn.
Past the last cone you gear up to 3 
Once you get the rhythm, it is done before you know it.
Going too fast results in slowing down.
good luck.