Which component upgrade will produce more BASS?

In the past couple days I've been playing around with speakers location in my room. I have to leave them on the short wall,
but with moving the woofers a little closer to the long wall(about 3or 4 inches) and turning them inward seemed to help a little.
But the big improvement came when I installed an Acoustic Zen Tsunami PC that I had ordered, and put on my Pass Xono preamp. I noticed a huge improvement when I put on the Beatles Sgt Pepper. Paul' Bass riffs were much more present than before. I also plan on upgrading the umbilical cord on the XONO.

I wpuld try moving them out to the middle of the room but close to the side walls, toed in quite a bit and move your listening position closer to the rear wall. You can then adjust your bass and imaging by moving backwards and forwards, back for more bass and more centerfill on multimiked recordings and forward for less boom and more envelopement on stereo miked recordings. I know I'm mixing issues but that's what you'll find. You'll be amazed at the added depth and you can totally taylor your bass response and room nodes with your listening position.

Ziggy,

In addition to the excellent suggestions you're trying now, here's one more.

Read this thread. The simple tonearm mod explained there:
- was specifically designed for OL and Rega arms,
- was specifically designed for Shelter, Denon and similar, low compliance cartridges and,
- confers a major improvement in the strength of bass and dynamics.

Dozens of people have tried this mod since it was developed in 2003. The results have been univerally positive. My own OL Silver became a giant killer arm. With this mod it outplayed a $3K Graham 2.2 and at least matched my $4K TriPlanar for bass clarity and strength, using the same Shelter cartridge on all three arms.

All it takes is $5 and an hour's time. Given your stated goals, I can't recommend this mod highly enough.

ditto Doug's suggestions, and also some clarification on my above post:

when I say to tailor bass and imaging by moving backwards and forwards, I mean moving your listening position, in case that wasn't clear.

Simple acoustical solution first. Install th speakers woofer out closer to the room corners. This changes the loading from a half space to.a quarter space and provides an immediate 3dB increase in bass. Avoid spacing that are related to the woofer height, so if you woofer is 24" off the floor, avoid 24" or 48" from the rear or side walls, as those will exaggerate resonance in the 125 and 250Hz range. 

Your speakers cross over at 200Hz to the mids, so you should be able to avoid too much 'thickening', chestyness, or muddiness on vocals. 

Room treatments are great but have little effect undr 200Hz. Just look at the published absorption curves for 1" and 2" panels. 

When you're satisfied you've optimized speaker placement, next would be the other mechanical transducer - your phon cart and arm. If your cart is a low compliance MC in a low mass arm, the cart/arm resonance will be too high and 'the tail wags the dog' - the stylus and cantilever just shove the arm around so you lose bass. Optimizing the mass and compliance allows the stylus and cantilever to move against the mass of the arm and bass improves dramatically. Go too far, and tracking, especially warped vinyl, suffers.

After that, tweak away, but don't expect miracles.

Finally, a subwoofer or new speakers that can move more LF air, e.g. 2-8" woofers are other options, or acquiring an amp with Dirac room equalization.

But most of all enjoy the music, and enjoy the journey.