Kenwood KD 2055 Upgrade or sell?

I have a Kenwood KD 2055 which I bought for $60 which I thought was a pretty good deal. I went in this weekend and fixed the humming from the motor(replaced old cracked bushings)and adjusted the auto return so it would let me finish the record(it would stick right before the end of the record). I would like to improve it even more, any suggestions? I already bought a Clearaudio Concept MM. Is the OEM tonearm good enough or should I upgrade it? What tonearm would work best? I know I would loose the auto functions :(