[carrera]

915 oh 915 what fun you are. So much fun. Particularly at the track.
My personal opinion is that the 915 is a real drivers car. Where as if I am feeling lazy or tired I will drive the g50. The 915 demands your full attention.
At the track the 915 is the box of choice for me. So much so that the g50 will see no more track time and return to being a garage queen.
The 915 feels really tough and durable. Whilst, dare I say, the g50 has lady like qualities. So smooth and light.
Primarily the difference is that you have to get to know the 915, the g50 you can just get in and drive.
As mentioned previously the problem with many 915's is that they require rebuilding because drivers did not become familiar with them and just tortured them. My 915 has 130,000 miles and feels as it did at 40,000.
First gear is not a problem and the 1st to 2nd shift is similar in both cars.
If you really want to feel connected to the car and you have some patience then the 915 is a friend you want to meet. Probably not as a daily driver for most folks but it works for me.

In closing I will add that my opinion and others are of little value as it is a personal choice that must be made by the individual driver.
Enjoy, and remember there are no bad Porsches just bad drivers that made them so.

disclaimer :your results may vary.