Depending on the sensitivity range of the amp and the preout voltage of your HU, you might be forced to accept not being able to turn the volume control up all the way. Other than that it's fine to have more power then you need.
1999 Buick Park Ave Ultra
Head Unit: JVC KWHDR720
EQ: Audiocontrol EQL
Front Stage: Hybrid Audio Technologies Imagine 5.25 mids, Morel Maximo tweets
Sub Stage: Boston G3 10", 0.5 cu ft sealed
Amp: PPI Phantom 900.4
Rear Fill: Boston SE953 6X9's