Just installed my GMS1 kit (North Carolina)
Today I went to the dealer and got the stage 1 kit put in at Hendrick Chevrolet in Cary, NC. They had no idea what they were doing. They thought it was a supercharged stage 1 kit at first, but then they figured it out and it took a whopping 3.5 hours to get it all finished. I was pretty pissed, but they were cool and charged me a fair price so I was satisfied in the end.
It is definitely more responsive and hits boost more quickly and I'm holding right at 20psi now under WOT. I still feel like I might have a boost leak just based on how the needle bounces off the 20 to about the 18 and back very quickly, but who knows. They didn't have a boost leak test setup at the dealership.
I think I'm gonna do charge piping and a downpipe and probably be done until I get some spare cash to grab the rest of the Hahn exhaust.
Now I just need to find a knowledgeable shop in North Carolina that can help me with dynoing and further upgrades. Anyone know of any?