Yo Dave,
Here's what I used:
It's the same shifter that Shelby feller used on some of the originals with C6s - his, for example & Cosby's - from a 1965 Mustang.
It's pretty easy to install. You can use it with the stock neutral safety switch. The shifter arm on the transmission needs to be for a floor shifter. I got one of those from (I think) John's Mustang in Houston.
The only other work involves changing the length of the shift rod by cutting and welding. This can be a simple task because you can use a shift rod with an elongated hole - most are made that way - the final length adjustment is done after it is installed by simply positioning it and tightening a nut.
I like the way it looks compared with the dominating look of some of the larger aftermarket shifters - but, to each his own - especially with Cobras!
Regards,
Tom