I have calculated the optimum shift points for the Audi A4 1.8tqm with a Wetterauer 1.0 bar chip.  The hp/torque data was taken from the Wetterauer web page and 205/55R16 tires were assumed.  The green lines are the rear-wheel power curves (in kWatts/10) for each forward gear, assuming no drivetrain losses, since the Wetterauer data was wheel data.  The cyan lines correspond to rear-wheel tractive force (in Newtons, again assuming no drivetrain losses since it' has already been accounted for) for each gear, while the yellow lines correspond to engine RPM.  As can be seen on the graph, the points where the power curves cross each other (equal power before and after the shift) also correspond to where the rear-wheel force curves cross each other (equal rear-wheel torque before and after the shift) and result in the best acceleration.  Please keep in mind that a different final drive ratio or tire size will shift the curves in the horizontal axis (shift point speed will be different), but the optimum shift point RPM will remain the same.