This is great news but I remain a bit wary. Obviously, the performance of this particular cartridge extends to 30 kHz or you wouldn't be getting good carrier lock. However, I would be curious how "flat" the frequency response is to 30 kHz. Since the manufacturer has only rated the cartridge to 25 kHz, there could be a (not insubstantial) dip in response after this point. To be honest, I'm not sure what impact this might have on CD-4 performance. If the dip isn't bad, perhaps no audible impact at all, except for maybe forcing you to turn up the volume louder than you otherwise might need to. So, I guess letting your ears be the judge is the best course! I'm glad its sounding good! The only caveat to recommending this to others would be that manufacturing quality may vary as to performance outside of the manufacturers specifications on an individual basis.