It is quite important to get a good SUT, but equally important to get one that synergizes well with the cartridge. A stepup that sounds great with one cartridge may not sound nearly so good with another, even after very careful impedance adjustment.
I haven't heard the Denon stepups, though one would "assume" they'd be a good match for their cartridges. Of the 4 or 5 SUT's I have heard the best match with a 103/103R were a friend's Cotters. They won't be easy to find used, but worth it if you can.
A really good active MC phono stage will outperform most (if not all) SUT's, at least IME. But good MC stages are difficult to design and costly to build. The ones I know that outperform a good SUT are well beyond your budget (judging your budget by the other components you're using). I think it would be reasonable to stick with SUT's for now. IME they're a value leading way to use value leading LOMC's like the 103.
My $.02
I haven't heard the Denon stepups, though one would "assume" they'd be a good match for their cartridges. Of the 4 or 5 SUT's I have heard the best match with a 103/103R were a friend's Cotters. They won't be easy to find used, but worth it if you can.
A really good active MC phono stage will outperform most (if not all) SUT's, at least IME. But good MC stages are difficult to design and costly to build. The ones I know that outperform a good SUT are well beyond your budget (judging your budget by the other components you're using). I think it would be reasonable to stick with SUT's for now. IME they're a value leading way to use value leading LOMC's like the 103.
My $.02