There are two differing forms of turbo controllers. There's the Press and Stay, in which you set the button and it fires til you un-turbo it, then there's press and fire, which allows you to hot key any- and sometimes all- buttons to autofire, so that they autofire only when pressed. The latter could be used for Boost, though you should still play it safe.

And no, I generally do not endorse Autofire controllers and the like, especially not in comp play, but damn are the fun sometimes.