I have had the K & M elect. controle for a couple of months.
It really firms up the shifts. Although they say not to use it in the firmest position as a daily driver as it is too hard on the pump. With the three position switch mounted just below the dash you can just flick it to firmest if you want to run the car next to you at a light.
For about $40. it's worth it. I've spent more and got less on other crap over the years.