A couple companies do make shift kits. I can't remember what the companies names are, but they basically look like a 6 sided star. The grooves in the star are a bit deaper than the grooves on the stock one. This means that when you shift it will make it firmer and you won't miss shifts near as much as you use to. I think they retail for a couple hundred bucks max. I don't know if you could call this an actual shift kit, it pretty much only prevents missed shifts, not necessarily makes it any smoother.
Life is short, but sweet for certain...