No problem at all. I can build the subs without the amps. Also you might want to try the Grandes without the sub at first. If you like the bass response, I would leave it at that and save the money for other equipment or more music.
Thanks for bringing up that quote. I have to delete it as I'm not building those subs. I experimented with the Dynaudio and Scanspeak variovents ( Aperiodic damping)in closed box subs. The result wasn't what I was expecting.