[SD987]

Regarding the rev history stored in the car's "memory", that Houston C4S commented on, the 986 records two types of events. One being bouncing off the rev limiter and two being an over-rev caused by a downshift. The latter code may negatively affect your reception when submitting a warranty claim to Porsche.

The 987 records rev history in certain high-rev ranges (six levels), with a median range (level 3) being up to 7,900.

Regarding shift points: the Power/Torque chart for your model should be in the back of your owners manual, but if you haven't seen it, the attached one shows an 04 986 and an 05 987 which will be similar to your 1997-06. The chart pretty clearly shows what you're missing out on in the Box by shifting early (variocam for example, doesn't kick in until 4200 rpm - one reason they don't want you exceeding this point during break-in). The chart also illustrates Randall's comment that at a certain point in the cycle you'll experience diminishing returns.