I think what you are talking about comes from the drag guys tuning their hedder collectors. What they do is run their collectors long, fire up the car and let it run. They then take a plastic rod and run it from the hedder, down the collector and where it stops melting is where they cut the pipe. At tht point it is said that exhaust is "tuned" for optimum torque.
Having said that though, I do agree (as I've "heard") that the crossover (X pipes are better) should be as close to the collector as possible. But as was said eilier, a balance pipe late in the exhaust is better than not having one at all, IMO, if for nothing more than smoothing out that exhaust note...
