JB4 Shifting Issues (6MT)

Hey guys,

I was told by a friend of mine with a 6MT 435 that the stage 2 JB4s running E85 are having trouble shifting quickly and it is an issue with the jb4. He also told me he's heard of a few cases just like his. Anyone else having trouble like this? Ill be installing a JB4 in my car next week so Im a little concerned.

Thanks in advance!