Believe me, your nervousness will very fast give way to the addiction this awesome device will cause.

Seriously, the InSim can do everything that is integrated in the game, but hidden in normal gameplay. Meaning, it just makes options easy to use, which are there already. So no conflicts like with many hacks. Plus, you'd need a hell of a lot of different hacks to get close to the functionality InSim provides.
And InSim won't break your game. There may be little problems if you use the wrong version for your EP, but all you have to do in that case is take it out of the downloads folder and all's well again.

I haven't been able to live without InSim for years now...
