As far as I know, the official PS3 version is unobtainable unless you downloaded it back in the day when it was available. It was also extremely buggy so it probably isn't viable for speedruns anyway.

From what I've seen, PSN is much faster than PS2 in terms of loads but it's still way slower than XBOX. Also, yeah, it was very buggy.

I suppose it was just added for the sake that it was, technically, an official version.

yeah, when they added it to the PSN it was taken down not that long afterwards because it was so buggy, so now the only way to play it on PS3 is to have a backwards compatible one