Originally Posted by mixja
284 and 292 are the duration of the cams - basically how long the cam is open. The longer the duration basically the greater the amount of air the cams can let into the engine.
Longer duration cams will shift your power band to the right - so give you more power at the expense of torque down low. In essence you don't gain any area under the curve generally, but for racing type applications, obviously you want all of your torque at high RPMs to make more power.
Without a doubt changing the camshafts would require retuning to get the most out of them. Personally on a car with variable intake and exhaust camshaft timing, I wouldn't mess with the camshafts unless it was from a very reputable tuner (e.g. Dinan) who had done the extensive R&D and fine tuning (i.e. offering in a "package" with camshafts and appropriate tune) necessary for this type of modification on this type of engine.
Schrick is a reputable German engine components manufacturer. They have been making engine components for years, I'm gonna bet that they make the stock cams for the S65.
Anyone who has been in the VW tuning scene is familiar with Schrick....... they make good parts that make good solid gains, albeit not huge gains. Schrick 264/260 cams for the VW 2.8l 12V VR6 gave a nice bump in low to mid range torque along with a bit of top-end horsepower. Schrick 268 cams for the VW 2.8l 12V VR6 gave a bigger bump in top-end horsepower while maintaining 95% of the torque curve.
I would say that the 284 Cams for the S65 will make some power and will maintain most of the torque in the low-end due to their milder design. The 292 Cams will definitely make more high-end horsepower but may lose a little more low-end than the 284....... I bet with these and the proper valve springs the S65 will spin to 8750 or 9000 RPM
I may look into these since I am interested in keeping my M3 NA.