Add a Subwoofer to my Vandersteen 1ce s or replace with Revel Concerta2 F36

Hey Audiogon community,
    Perhaps you guy can help here. I have a VPI Scout with Sound Smith Zephyr III Cartridge running into a Musical Fidelity v-LPS that runs into a NAD VISO 5 Receiver and back out to a pair of Vandersteen 1ce's. Since I recently bought the Zephyr III, it revealed some inadequacies, and I am in upgrade mode. My audio advisor from Brooks Berdan suggested I start with the speakers. Mind you, I Love my Vandersteens but wish there was deeper bass realism. I have been listening to the Revel concerta2 F36  recently with a Cronus Magnus powering them via some entry level Oracle turntable. I like the F36 a lot, and feel like they would give me more full range dynamics especially on the low end. I am looking at upgrading to the Rogue Cronus Magnus soon as well. And am hoping that upgrading to the F36 is the smarter choice than adding a sub that would seamlessly integrate. Any thought would be appreciated. Thank you.