Performance / Gpx question

Hi folks - not a noob to GP4 or Gpx or CSM or anything, but I just had a couple of niggling questions that I can't find addressed anywhere.

When playing certain mods (csm), it seems as if the performance file selector is grayed out and can't be changed, as it is obviously on an automatic load function for each single grand prix you choose.
I was wondering how it can be changed so you can manually select a performace.txt?

My other question is probably of similar ease to those who know what they're doing!
On some mods, like 1995/1994 to name two, the '9' function for the gpx overlays (showing live timing basically) are much nicer than the standard gpx ones used for the original game and some other mods.
What would I have to do to use a certain version on any particular mod?

Thanks in advance for any replies - like I said, I had a big look to see if this was addressed before, but failed to find anything.

ps.. Hi! Long time GP4 player, long time forum visitor and overseer