What do we know about the z1 lower intake manifold?

Mysilverz

I installed the plenum and lost 7whp. I assumed this was because I need a tune so I went ahead and installed the manifold as well. I went to Rob at topspeed Motorsports and had him tune the car. I was down by about 17whp when I got to him. After he tuned the car with ecutek I gained 15whp with the tune. So I was still under my original number so we swapped back the stock plenum. I reset the ecu and did two Dyno runs at operating temperature. Then we changed the plenum, we didn't even take the car off the Dyno. Brought the car back up to operating temperature and did two more runs. I gained 5whp going back to stock but haven't tuned it since. I'm going to swap back the stock lower manifold next and see what happens.