Jeff, did you get FHS's spring?
Mike

I've just installed and started testing mine.
Very similar in size to FHS's spring.

Ya, tried it on Sat. I had an eye bolt and the exact spring from above bought a home depot. I hit 15psi! I tried adding some chain links to eye bolt (eye bolt was already fully unscrewed) and was still spiking to 13psi, before settling to 10 psi. I don't have enough fueling for 15psi as my a/f ratios went way lean and I heard some pinging (let off right away). I may go with a lighter spring now. I guess I should be happy with my 1.5-2psi variance.

I didn't end up using the spring as is off the shelf. I got the WOAH psi when I first tried it as well. I just had to stretch the spring coils out a bit to lighten up the tension back into the 10-12 psi range and I had to loosen or tighten the actuator arm as well. I was using a MBC at the time too. Now, after much fussing about, I can use just the spring and the wastgate actuator. The other springs I tried to use were either WAY too tight or WAY too loose. Completely unusable with my particular set up.

I stretched out some coils on the spring I used too.