what speaker to replace atc scm35

I have a Naim cds3 cd player through an Audionet pre G2
preamplifier and a Bryston 4bsst2 power amplifier. It is very good but I would like just a little more bass extension with a similar sound. Any not outrageously expensive suggestions will be welcomed.
Give active ATCs in your price range a listen, active ones outperfrom passive ones significantly.
Yeah, what those guys said!
Have you tried adding a subwoofer?