[GP125] 94 to 95 TZ Shift Drum

I'm thinking about upgrading my '94 TZ to the '95 spec shift drum.  Everything
I read and hear says it makes for much easier shifting.  The questions:  Is
this an easy swap of parts or are there other changes that make the parts
non-interchangeable?  Which parts exactly need swapping?  Is it just the shift
cam assembly?  Will the existing forks all match up properly?  Thanks for the
info!  Oh one more question, any idea how much a shift cam assembly runs?