Altron
From Multiversal Omnipedia
Altron was an upgraded version of the Gundam Shenlong, model number XXXG-01S2. Armed with better weaponry, it (like its predecessor) was piloted by Chang Wufei. It was later replaced by another upgraded version, Nataku.
Comments
Note that according to the creators of the OVA Endless Waltz, the Nataku was actually how the Altron had looked all along.