I would suspect the Moon amps will be as good or better than the IA since the PA/Amp will be separated. The IA is no slouch by any means, but you would need to stay in the same line, of amps, to get a fair comparison. Moon’s Evolution series amps are among the best (thats subjective)
I ment to say the 600i, had no problem driving the C-4, regardless of volume levels everything was clean and detailed.
Not to create any additional confusion but Modwright amps are also worth consideration and audition if possible.