Optimizing TNT, Triplanar, Transfiguration Temper


I'm writing because of a combination of frustration and potential in my turntable set-up. I have never gotten the sound from the system that I expected, but feel that I am beginning to glimpse the potential of achieving it. I have made some changes recently that have led to more changes that have brought me closer to what I have heard from other systems with similar components. I am hoping someone can guide me toward finally obtaining the basic qualities that I'm looking for and I can fine-tune from there.
What I have heard before from lesser components and am not getting is the sound of the transients jumping off the record. I thought this problem was merely from the characteristics of the Transfiguration Temper Supreme, but with some modifications of the table I am beginning to hear it and wanted to see if I could bring it out further.
Let me back-track and tell you my components and what modifications I have made so far. I am running a VPI TNT upgraded to 4 (w/ the rectangle cutout for the motor), with the original motor and just added an SDS (which made the biggest improvement), a Wheaton Triplanar tonearm upgraded to VI, and a Transfiguration Temper Supreme cartridge.
When I upgraded to the SDS, the timing and solidity of the sound improved dramatically. I then found that using a single belt directly from the motor to the table actually outperformed the three-pully design originally designed for the table, perhaps with some trade-offs, i.e. voices sound clearer and better-defined, but piano may have a little less air and realism.
Finally, the table sits behind the speakers, particularly the left speaker. Moving the speaker forward a few inches seemed to significantly clean up the sound, so vibrations from the back of the (B & W 803) speaker may be muddying the water. My other components are Spectral DMC-20 and DMA-180 and MIT/Spectral reference cables.
Like I said, I am glimpsing the potential of this setup, and the music is starting to clean up and jump off the record, but it's just not quite there. I feel like I'm missing something simple and would like advice before making a lot of changes. I think I've set the cartridge up properly with regard to alignment, azimuth, VTA and no anti-skate. I have not removed the damping trough yet, and that is the next thing I was thinking to try. I am planning to try to further isolate the table from the speakers - the cable lengths prevent me from totally moving the preamp and turntable. I was also considering using different belts or string/dental floss etc. Another possibility is investing in a single-motor flywheel, which also would not use the three pulleys included with the TNT turntable. But, I feel that there is something simple and straightforward with the front-end that I am missing. Any advice?
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Correction: 'I just changed the cartridge loading from 100 to 800 ohms...' (not 300 ohms). After listening several hours, the improvement persists. With the exception of my preamp still giving me problems intermittently, I can say that I have very little to complain about now, and I can just sit back and enjoy the music! Regarding the cartridge, it's very neutral, rhythmic, engaging, solid, and really just gets out of the way of the music. It's neutrality and openness are very similar to the Temper Supreme, but the solidity, rhythmicity, and presence all surpass the qualities of my (old) TS. Also, the soundstage is more consistently impressive and especially deeper than the TS. It still may not have the attack or flashiness that some cartridges do, but the transients are fast, detailed, and accurate and in no way lacking. I just don't think it adds punch to the playback, and this is a good thing. I'm sure the cartridge isn't completely broken in yet, as it still seems to be getting better and better and more open the longer I play it.
Update: So far very satisfied with TNT, Triplanar, Transfiguration Phoenix. The Phoenix has opened up a lot with break in. I don't have the complaints I had before of lack of transient response, and things overall seem more stable. I also moved the turntable to the other (right) side of the amp (though still behind the other speaker). I was very careful in setup, and it seems more stable. I am thoroughly enjoying music again!
Comparisons to your old Temper ... ?

or has it just been too long ago to remember
It's hard to remember, and unfortunately (or fortunately for me financially) I traded it in, so I can't do a direct comparison. But, the biggest differences I note are: it's not as laid back as the temper and maybe not quite as silky smooth, but at least as detailed, a little fuller-sounding, transients are much better, and it's more solid and coherent. Everything sounds 'right', not overbearing or any one thing standing out, but I think fitting well with my system. I think the Phoenix is more accurate and more revealing of both good and bad recordings. Overall, it's a better cartridge than the Temper I traded in, but keep in mind it was a very old Temper Supreme.