Anime First: Conceived originally as an anime, it had two manga adaptations. The one done by Keiko Okamoto was released as a companion to the anime, while the other one drawn by Asamiya himself was serialized around the end of the first season.
The anime had an official home release on DVD by Viz Media in 2004. If you search right, it's still possible to get some DVD's copies at very low prices from secondhand sellers... however, only 18 episodes out of 52 were released distributed in four volumes. Of course, there are copies in the net of all the episodes... from the Latinamerican dub, mostly (that used the English translated scripts for its dub), or the Brazilian Portuguese dub, too. Don't count with luck if you are looking for fansubs, though.
And there is Okamoto's manga adaptation. Tokyopop only released the first part of the manga and the volumes can still be obtainable from second hand sellers at very low prices. Corrector Yui Ver.2, though...?
Meanwhile the series at least got a quite reception in Latin America and Brazil by the time (however, that depends on whom you ask) in earlier 2000s on TV, the same couldn't be applied to the USA. The anime could have worked so well on TV, being in that time that anime series like Card Captor Sakura or Sailor Moon were having a good reception and having it mixed with the then also recent elements of technology exposed in media like The Matrix could also have helped. Yui, being a girl who Jumped at the Call because she wanted to be a Magical Girl since she was a fan of the genre itself. Although Viz Media announced at the time that they were releasing the series, they just ended up releasing 18 out of 52 episodes in DVD, due to low sales.
And these low sales didn't just affected the anime release, but the Okamoto's manga adaptation. Tokyopop gave up the license not so long after publishing the last volume of the first series. There's no way to get Corrector Yui Ver.2 if you don't give a try in searching at Japanese auction sites. Same is also applied to Asamiya's adaptation.
In the LA dub this is much more common to find than the Japanese version. Ecco and Reiko have the same dub actress, but barely talk to each other in a scene. War Wolf and Grosser are another examples, though their dub actor manages to sound different between one and another when both appear in the same scene.
The Japanese version, however, applies Fridge Brilliance and Fridge Logic cases. Grosser and Inukai share Mugihito as their voice actor, when the viewer finds out that Inukai created Grosser at his own image - he would find him wherever he was because he was thinking alike as his own creator. Fridge Logic happens when Takashi Matsuyama started playing as War Wolf in the whole series... until the climax of the season happens, and Synchro starts talking to him via a prerecorded message to reveal he was War Wolf all along.
In one of the volumes of Asamiya's manga, the anime series planner commented about some plots that were cut due to some issues they were having when working in the animation, especially involving some ideas for networks, such as episodes based on a Mystery Net, an Arabian Net, a net based on Yui's Four Panel Theater, and a Future Net that would have involved a 'Game of Life' simulation.
Apparently, back in the day, Viz Media acquired the Kia Asamiya's manga rights to publish it in America.