Has anyone done the Cobb tune on a GT4/Spyder?
 

I'm just curious if the Cobb tune provides a noticeable difference in the power of the car? Seems like a good value if the performance gain feels significant.

Yes I did. Stage 1 meaning no other mods such as headers etc. When I put it on at first the car immediately felt more responsive, and I thought I could feel the increase in power; however, I was wondering whether that could simply be placebo effect.

I occasionally flash back to stock and it's when I flash back to stock that I feel a clear difference. In other words I feel it much more when taking it away than adding it on, if that makes sense.

It is not a major difference, but I think it is noticeable and worth it. Besides, it is fun to see the hp orange ball on the dash display go slightly outside of the chart range when you gun it ;-)