I guess it boils down to are you happy with the backshift now? does the sled overshift from a dead stop to wide open now, meaning it revs up quickly and then has a bog to it about 10feet out, then recovers and takes off? I always like to run the least amount of pretension as possible without producing the problem above, the sled will run better and have better topend this way. Its something you have to tune into the exact sled its being used on.