Engine vibration after replacing the fuel pump with a High-Pressure fuel pump?

The vehicle listed above, Ecotec 2.4L. Background: I successfully replaced the timing and balance shaft chains, all the sprockets, tensioners, guides, and cam phasers. The engine was then quieter and smoother than it's ever been. Yay me! I also had a problem with the engine running on and fuel in the oil. So, a week later I replaced the high-pressure fuel pump. Immediately on startup I noticed a slight vibration and rumbling noise at idle that was not there until I replaced the fuel pump. No codes, no stalls or lack of acceleration, just slightly rougher idle and slight vibration since the new HP fuel pump. I know the pump is cam driven and the noise almost sounds like it's coming from the phaser end of the intake cam but can a new (stiffer?) Pump cause this? It was idling perfectly smooth beforehand.