Now this is going to be in the game, you must make a system that it's not possible to switch afger every race, to get the partners that are best for the next track
I agree with Yuri. Eventually people will find the best combo's for each track and just change their suppliers around every race so the end result will make the new suppliers pointless. But I think locking the suppliers in for an entire season is a little harsh, especially when people are still trying to figure them all out when they are new. Maybe like Victor said, lock them in for x amount of races... Maybe 5, or 3 sounds reasonable too.