OK, so on my previous post you can't visualize my story, so I decided to upload the screenshots using my modified viewers. Orange is Player1's path, SkyBlue is Player2's Path.

Taking the path around BloodStream to avoid missing turns:

Riding on the BloodStream early to get free acceleration:

Here are the bigger screenshots: PFTest1 and PFTest2

I suggest you modify your viewers for debugging your PathFinder. I'm not gonna releasy mine cos it's buggy and it doesn't allow you to record game and playback any replays. Hence its use is only for debugging the pathfinder and not for testing my bots before uploading.

Guess which one will reach goal faster?
The BloodStream’s direction is EastWest.
 
Player1 (green) uses a custom pathfinder and Player2 (blue) uses the default pathfinder. It seems Player1 will lose the race because it’s going to take the long route avoiding the BloodStream.

But after a few turns…
 
Player1 (green) is winning the race. And Player1 will actually win the race if you watch PFTest1.replay

Let’s reverse the direction of the BloodStream (now going WestEast):
 
As can be seen, Player1 (green) will choose to “ride” the BloodStream earlier because it’s going to make him travel to the right direction faster. Player1 will win the race if you watch PFTest2.replay.

Click Here to get the replays + missions.

So I’m on the side who says you should opt to create your own custom pathfinder…if you have lots of time tinkering :-)