I really hate to have to keep bringing up this subject, because it smacks of self-promotion, but have any of you read the "Strange Tonearm Tweak" thread on this analog forum?
It works great on standard RB250 arms, and makes a hell of an improvement in sound for about $1 in cost. I promise that I am not going to try to sell you anything. All the instructions and theory is on the thread. You can make it yourself in a few minutes for under a dollar. The improvement is astonishing, and is verfied by many users on the Strange Tonearm Tweak thread. It has been in use by me and others for over 2 years now, with excellent results and no down-side, as long as you use cartridges of 15cu compliance or lower. This is no joke, it is a great mod for pennies, and may result in more improvement to your sound than spending $500 or more on a tonearm upgrade. If you really want to get it right, then get the OL tonearm upgrade AND do the Strange Tonearm Tweak(HiFi mod).