Counter weighting a shaft, Have you done it?

We had a guy out at our club this weekend selling and demoing a system for counter weighting shafts. The system he was selling was called Tour Lock Pro. http://www.tourlockpro.com/tourlockpro.htm. Im not a salesman for them or anything so im not pushing the product I just want to know if any of you have tried counter weighting your clubs and how it worked out.

I had him put one in mine and it seemed to help me get a little more distance on the range. He added a shaft weight and a weight at the top of the shaft. I played 9 holes and the shaft started feeling too heavy after I got a little tired. I had him take out the weight at the top and it we better.

My question is, does this weight in the shaft change the flex and overall performance of the shaft and do you think it can damage the shaft after time. It seems like having a weight in the shaft can modify the flex and possibly put undue stress on it.

He also added one to my sons driver to see if it could help his slice. Apparently if you add the weight higher or lower in the shaft it will make a difference. It did not seem to help.

Ill give mine a few rounds to see how it works out I just wanted to know if anyone had or is using them and what you have experienced.

I have messed a bit with back weighting by having lead tape under the grips of a couple of drivers and putters, but the jury is out as to wether it did any good.

We are about to review the Heavy Driver here at THP, and this is part of the technology behind the Heavy line of clubs and putters. The Heavy irons and hybrid testing is underway as well.

It would be nice if the Heavy Driver's weight were adjust-able.