My point is that I have read here and in other forums that the .357 Sig is a better more consistent penetrater of auto bodies and auto glass than other service calibers. I've seen no evidence that this is true. I have seen that various loads of 9mm, .38 Super, 40 and 45 acp can all penetrate auto and truck bodies and glass just fine. The links above show that as well
Most of the tests I have seen compare the .357sig to the 9mm and not to the .45acp since they are the same size bullet. Every test I have seen or done support the idea that it outperforms the 9mm pretty handily. I would not call it more powerful than the .45acp but you can get more rounds in a similar platform and it performs well enough to make it worth it. I have seen some test that do seem to indicate that it is an extremely good penetrator of metal objects though...even better than .45acp rounds.