Carey wrote: "While I would do a Berg 5 speed if someone desired, I'd rather see the car with a 901 or 915, but that is just my personal taste..."
Both are good transmissions. I have had both. The 901 with the dogleg 1st takes some getting used to, as it's a long shift to 2nd, but the H pattern once you get out of 1st is nice. Porsche figured having gears 2-5 in an H pattern is better for racing, and 1st gear is only to get you rolling.
The 915 that I currently is also good, but 915 transmissions are not known for their smooth 1st to 2nd shift. The 4th to 5th shift is long, but smooth.
Five speeds is the way to go.