The gearing on my red lexus v8 powered car is all wrong so I need to swap the diff for a higher ratio. The one currently in the car is a 3.9 and I would like to go as high as possible to get the cruising revs down. This car is primarily going to be a GT so the more relaxed the drive the better. I could go for a R200 3.54 but that will only make a small different to the revs at a given speed. I do have a 3.36 R180 and a spare R180 quaif so I'm considering this as an option. I know the open R180 could be an issue with spider gear problems so replacing this with the quaif should cure this. Anyone have some real world experience of R180 diff problems?