best upgrade for 'standard' LP12

I have a Linn LP12/Rega RB300/Grado Sonata which is level and on a good (Audiotech)stand, and am wondering what is a good upgrade that does not involve tearing the table or tonearm apart?

Are the Linn upgrades a reasonable alternative to the Origin and others that are highly touted?

I do not have the trampolin or Lingo, what kind of improvements do these make?

The sound I am getting now has a little midbass ripeness (or lack of definition in the mid/lower bass) and is slightly thin in the upper end. The midrange is very nice and has an intimate quality and the 'Linn beat' seems alive and well.

Overall I am very happy with my setup but wonder if there is a few simple lower cost things I can do that will help these areas.

thanks

Phil