I disagree about replacing the Rega. The Rega is a great match for this TT and an SME (Im asuming a 309 IV or V) or a graham would be overkill. I have set up and restored many of these and they are a fine table. To get noticably better performance you will have to spend serious money. Check the AR forum on vinyl engine and as mentioned above Dave, also Sound of the wood Eric Whitacre. The most beneficial upgrade is an improved motor and power supply. If you want you can go nuts with upgrades and teaks on this table which is one of the things that makes it so much fun to own.
Rick
Rick