Here's what I think.
1st, I think is sounded good so I did it and finished it about an hour ago and it took about 20-25 minutes in all from 1st turn on bolt to closing the hood.
2nd, I think there is a definite increase in power and pull between about 1500 and 4500 RPM's. Not only that but there is now a smoothness to the power that I haven't felt in this car through the powerband all the way to redline. I did 2 very unscientific 0-60 runs with a digital chorno and pulled 6.13 and 6.09 respectively. The best I had done it the past was a 6.35. I have a step trans BTW and these runs where going M1, M2, etc and I'm hitting 60 in M2. Again, maybe just a fluke but if this truly can help drop .2-.3 seconds off of an auto, then it could take the 6-sp manual into 5.8-5.9 territory.
3rd, The hestitations I used to feel between 2-3K is gone, maybe this helped may not, but I drove for about 30-45 minutes after the job on both the highway and the city and it had stopped. I'll keep a eye on this and see if it returns.
4th, no noticable changes in sound of the car.
So to wrap it up, in the time I drove the car after doing it, I was nothing but pleased with the results. It's pretty easy to do and seems to have a good payoff. I'll give it 2 thumbs up.