I'd also like to know this. I have the FI headers now. Wanna know if there is big power gains going to the momentum or since I already have these just to keep them.

same question....

To compare properly you have to get the same car, on the same dyno, on the same day, with all temps the same (oil,coolant, humidity, etc).

I'm not sure why you would think these shorties make more power than the long tubes but I know they are close in terms of power.

Another thing for you to understand is that the "tune" plays a huge factor in final numbers. So to extract and compare it completely. Both of have to be tuned to max ability.

To simply bolt one on the dyno then bolt the other on and dyno does no just as each one will throw different AFRs and throw any current tune off and will affect how each one performs.

Any updates on this? Has anyone else made that kimd of power on Z1 headers?