Audio Research and CJ are at opposite ends of the sonic spectrum.
the sonic gap has been narrowing for some time now, at this point, their top of line pieces are rather convergent.... c-j gat and arc ref 6/10 are both very extended, impactful, excellent bass drive, with tube beauty and richness in the midband, and expansive, deep quite specific soundstaging
days of crystal clear fast grounded arc vs c-j’s honey colored beauty with sloppy bass and rolled off treble date back to circa 2000, when the arc sp-16 and c-j pv12 were current
c-j still dedicated to single ended connections while arc top stuff is balanced only... that is a major distinction that persists