Yeah, but we know that their engines were made to take advantage of better fuels if it became available. As a perk option I think it would be nice to include a few "what ifs" in the MA. Any and all perk options should of course be possible to disable for scenarios. As for how the game handles perks options, that can be changed; all the data should be loaded into variables anyway, so a simple drop down menu should be enough to change which FM is loaded into the variables. I hope to one day see a more usable perk system were we get to chose engine options (fuel quality, ADI, NOS etc.), loadout options including perked "experimental" loadouts and "what ifs". Things that were tested, but didn't make it into (full) production for some reason or another.