I know very little about cams but am doing the same rebuild currently and had the Webcam 163/86B suggested to me because I wanted some low-end torque. This is a dual-duration cam and I think that means the exhaust valve stays open for longer than the intake. This helps to overcome the problem with the restrictive exhaust port on the T-4 heads. I think Porsche 2.0L heads are a different story. I would email John at
www.aircooled.net as he was extremely helpful with my cam choice. Also, his prices are great and so is the service. Good luck!
Ben