buy these. You will use them it place of the messy silicon plus you get a gasket that goes between the shifter and handle, and they really do wonders to kill a lot of the buzz you get when you just use the silicon. Cobra Bob is the man!!
Technically, no. But it is so much easier than using messy silicone, with the added bonus of making your aftermarket shifter as quiet as the stock one. That was the main selling point for me, the ease of installing the shifter with the gasket was just icing on the cake. It's an awesome product that I can't recommend enough.
If you don't mind my asking, which shifter are you planning on buying? If you are still shopping, the MGW has my vote. Whatever you choose is worlds better than the stock shifter though.
So far, I've heard good things about Pro 5.0, Steeda Tri-Ax and MGW, but I'm gonna do a whole lot more research before buying. Thanks for answering all my questions.