Budget Strategies forTightening up Bass?

My system: Opera Consonance 120 Linear CDP, Extensively modded Jolida 302B, Silverline SR 17.5 monitors. AudioArt Speaker wire. Various IC's. Short of buying a sub, what is biggest bang-for-buck upgrade to tighten bass? Wire? PowerConditioning? ("currently" I have just an upgraded cryo-treated outlet) Better footers? (I have vibrapods and cones). I've got about $350 to spend on this... I know-- that's not much-- maybe my goal and my budget are mutually exclusive. Still, any suggestions would be appreciated!
Rcprince-- I tried moving speakers 4" further away from back wall-- seemed to make a difference. Will experiment further.
I've found that sorbothane under a CDP makes the bass 'riper', while inverted brass cones make it 'tighter'.

your mileage may vary...

you might also look into a DAC. the different flavors of D to A vary enormously between brands (e.g. theta = kind of gutsy while sony = analogue-y). you'd have to audition them in your system to see if that addresses the problem.
try a VenHaus DIY PC <$100 ea

you may realize other benefits as well

power cords make a big difference and may be all you need
Speaker cable and power cords. A good power cord will tighten things up - 'A LOT'.