Would frequency response of cartridge determine purchase?

Are you sure that the load capacitance seen by the cartridge when you tested it wasn't too high?  (The load capacitance seen by the cartridge being the sum of the capacitance of the phono cable, which is proportional to length, and the capacitance of the tonearm wiring, and the input capacitance of the phono stage).  100 pf is recommended for the Clearaudio Virtuoso V2, which is low enough to be hard to achieve in many cases.

If the load capacitance applied to a moving magnet cartridge is considerably higher than recommended, typically the result will be a frequency response rise in the mid to upper treble, probably followed by a frequency response dip at frequencies approaching 20 kHz.

Regards,
-- Al
 

The paper work that came with cartridge has a performance graph and showed the units performance when tested at factory.

I see in your thread from a few months ago that you are using the Clearaudio Concerto V2, a low output moving coil cartridge, not the much higher output moving magnet Virtuoso V2 cartridge used by the OP. Although you reported also experiencing excessive brightness. What did the performance graph you referred to show?

Regards,
-- Al