I got the TCC-750 that was listed/reviewed in the link below:
https://audiokarma.org/forums/index.php?threads/budget-lomc-preamp-shootout.975553/
I ultimately upgraded the power supply with one that delivered more current, but I can't say definitively that it made much of a difference. I want to say it did, but in all honesty, I can't differentiate between a small improvement and confirmation bias. I don't have any experience with the ART pre, but I have a couple ART mic preamps in my home recording studio; I would be comfortable purchasing and using one.
As for cartridges, as I mentioned earlier, I saw a dramatic improvement going from a red to blue cartridge. I'm nearly as bound by budgetary concerns as you and I was really hesitant to spend more than double the amount for the Blue than the Red, I just couldn't envision it making that significant of an improvement in SQ. While it had been many, many years since I'd invested in a cart, my recollection of 20 years ago was that a really good sounding cartridge and stylus was never more than $100, so it seemed preposterous to spend $240, right? I got one from amazon out of desperation- I didn't think it would make much of a difference and if it didn't, it was easy enough to return and get my money back. Installation was simple- Blue and Red use the same cartridge body and different styli, so I merely swiped the stylus and was off to the races. On first listen, I was simply astounded at the improvement. Going forward, I would not hesitate to get one again and have concluded that it's price point is likely the standard, going rate for a quality entry level cartridge. Others will be able to weigh in on other brands, but I am quite satisfied with the Ortofon Blue.