94 Z-28 6spd T56 Trans ... potential shifting problem... (sorry)?

Ok for those who read my first question my bad. I got mixed up. Anyway shifting from 1st gear into 2nd at a lower rpm is going from 1st to 4th. But shifting from 1st into 2nd at a higher rpm is normal. I was told it was a common gripe by other same generation z28 owners. And that all it needed was some "$75 wire harness" to byp that problem. Something about how it was a normal thing and others complain in forums about it all the time... any ideas? Thanks