How do you know your needing to boost those ranges, are you running graphs to determine, or just using your ears? A flat frequency response across the entire range is the most desired. Without proper placement, room treatments, multiple subs, etc. you may just have to live with what you have, welcome to the joys of subwoofers.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85