New cartridge or new turntable or both

A question for the forum.  I am contemplating buying a new turntable but wonder if a cartridge alone would suffice. I am running a Luxman PD284 with a Grado Red cartridge, Leben CS600 amplifier, LFD LE phono stage and vintage Spendor SP1 speakers.  With my Cal Audio Icon CD player or Linn Streamer the Spendors really shine but when I spin a record I lose detail and dynamics as well as wobbly bass.   I have seen people are paying a fair amount for used Luxmans and wonder if I should just try another cartridge; or should I just fess up and bring my turntable up to the level of the rest of my system  ( have been looking at VPI classic, and Analogue Works One tables).
Grados tend to be somewhat dull in the upper frequencies. I'd hazard a guess that an AT540ML cartridge at $250 would bring a lot of life to your rig. Worst case, it's a fine cartridge to bring to another table if you decide to replace the Luxman.