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.