Pothole, you are of course correct re: the transmission gear ratios. When I posted I was thinking of the differential/rear axle gear ratios, where a higher ratio of course means that the engine is revving higher at a given speed. I should also say that I agree that the gear ratios for both the 2.5 and the 2.7 were well-suited to the engines: my reference was to the suggestion that the gear ratios in the 2.5 would be ideal with a 2.7, something with which I disagree. The 2.5, with less torque and a narrower torque band than the 2.7, needed lower transmission ratios and more shifting than the 2.7.
I should also point out that there was virtually no weight increase as between the 1999 2.5 and the 2000 2.7 (about 20 lbs as I recall - although as I have the actual published curb weights for both from Porsche somewhere, I will check and report back if significantly higher). The subsequent base models did increase in weight with the addition of the padded top/cupholders etc. in 2001 and more significantly, the extra top bow, glasss rear window and glove box in 2003.
For the 2000 2.7, as I recall Porsche listed a 0-60 MPH time that was .3 seconds quicker than the 2.5 and the following site shows relative performance in both 0 - 60 and 1/4 mile times.
Porsche 0-60 Times & Porsche Quarter Mile Times | Porsche 911 Carrera 0-60, 944 Turbo, GT2, Boxster S, Cayman R, GT3 and Porsche Cayenne 0 to 60 stats!
This confirms that the 2000 2.7 is .3 seconds faster to 60 MPH and the time differential in the 1/4 mile is nearly 3/4 of a second: 14. 8 seconds for the 1999 2.5 and 14.1 for the 2000 2.7. Not huge, but significant IMO. What is more significant from a driving perspective, however, is the flatter torque curve and its impact on driveability. I'll try to dig up some tests of the 2.7 from back around 2000 by Porsche Excellence magazine, but as I recall the author of one of those tests was the owner of a 2.5. He indicated that, from his hands-on experience in both, the 2.7 seemed closer in performance to the 3.2 than the original 2.5.
The 2.5 is an incredible car, make no mistake about it. However, I believe that it is important that we don't try to get into revisionist history. The changes that Porsche made to the displacement, fuel injection and gear ratios in the 2.7 were done in order to improve both performance and flexibility and, in conjunction with the 3.2 'S' that was introduced in the same year, to answer some of the criticisms of the performance of the 2.5.
Brad