I agree with those who say change the cartridge. Put a Lyra Dorian in there and you will be amazed at the difference. If you want to spend less, I recommend a Goldring Eroica. Very good cart for under a grand. That being said, I upgraded from a Rega 600 arm to a used Ekos and it was a big upgrade - as it should be for twice the price used and over 3x the new price. Contrary to what's said around here very often, sometimes the more expensive stuff IS better.
Tone arm upgrade
I'm currently using a Rega RB300 modded tonearm ( aftermarket wiring harness and counterweight). I'd like to consider a step up, have been keeping my eye open for a good condition used Linn Itok arm. Is this the right path or in the $1~$2k price range is I there another good alternative?