Wrapping the copper wire around the tubing and soldering it in place wasn't so difficult. It was time consuming though. It WAS difficult to slide that through the hose though. I had a difficult time getting it through 5/8" ID braided pvc hose.
I'm not a physics or engineering major, but I'm not so sure that the copper wire wrap for 'turbulence' provides a SIGNIFICANT increase in performance of this type of chiller. I think the best performance boost a counterflow chiller can get is by having cold water to pump through it. I have a 50' immersion chiller that I built a long time ago and during the warmer summer months when my ground water out of the spigot is 85°, I plan to use the immersion chiller in a cooler full of ice water as a pre-chiller for the water I'm pumping through the counterflow chiller.