I was experiencing increasing hesitation the last year in my wife's 1995 960 with 89K. She only drives around town, probably lots of carbon build up. Anyhow, it got to the point the last couple weeks where it was starting to idle extremely rough and die at traffic lights once the engine was fully warm. I started by changing the fuel filter, then the spark plugs. Both were due, but there was only mild improvement.

So a couple days ago I bought two cans of seafoam and followed these instructions:

http://forums.nicoclub.com/how-to-seafoam-your-engine-the-right-way-complete-diy-t126583.html

Used the vacuum line off of the power assist, extended it with a 2ft piece of vacuum tubing to sip the can contents into the cylinders while my son kept the RPMs at around 2K. So it was 1/2 can through the vacuum, a bit more than 1/2 a can into the engine oil, and nearly a full can into the gas tank with about 10 gallons in it.

Took it for a drive and the problem was completely solved. I guess you can say I'm a believer now. Plan to change my oil in a couple days once I get about 100-120 miles on this cleansing.