I have one. Well it's the Novitec one but they are basically the same. It's a pleasure to use, nice short throw. No notching or anything (stock one could get a bit notchy at times), you all know the F40 gearbox is a bit fidgety. Solved now with warm weather, new oil and short shift.
Friends that drove my car immediately noticed that something "cooler" was there.
It is a bit expensive for what it is eg. a machined piece of metal, but I guess if we wanted mass market stuff, we would of bought Hondas.