Firstly, all races on PAL begin after the green lights are turned OFF instead of ON, That is around 1 second later than on NTSC. Therefore NTSC saves around one second per race for full runs.

Secondly, PAL load-times seem to be a few seconds longer compared to NTSC.

Now for the real DEALBREAKER... Every single race is one lap longer on PAL! That means PAL runners lose "X" amount of time per lap multiplied by "Y", the number of races in the category!

Tl;dr PAL is not a viable option to speedrun this game competitively, unless you want to do ILs, as the timing starts from the moment where movement is possible.