Idk, I never saw much point in a pif replacement unless you're stuck with a PAL console. That's assuming it's 100% bug free which is not likely, as some games still need to talk with the CIC (Banjo Tooie decrypts its level descriptors with response keys from the 6105)
Even so, if you swap out the video crystal and pin strapping to get 48.68mhz vclk, you are in good shape to use a flashcart to softboot any game into NTSC with perfect timing.
All of the unique PAL titles have ntsc patches available, and most of the PAL ports are inferior to their NTSC versions. And when you're already sacrificing a donor console, it's just a chip to swap over..