I used one of these before and wouldn't recommend installing a remote start on a manual tranny without it. I've seen people would have and trust me, eventually your going to forget that your car is not in neutral and BAM there goes your front end.
what it the module does it tell your remote start that it is "safe" to turn your car on.
I actually bought it and started to install it. So far I ran the black/purple harness to the clutch pedal switch. Once i get my audio stuff in, i'll finish the install so i don't have to pull the center console out a bunch of times.
Not sure where to hide all these modules either. I was thinking of buying some aluminum and making a cage and then bolting it in somewhere in the dash to make it harder to access. Then pull the wires through in metal tubes so they can't be cut. I know its overkill, but it doesn't cost much at all to do..haha I could also run a bracket to the radio from the cage so no one can simply remove the headunit either. Plus with 4 speakers under the dash, and the underhood siren, you won't be in and around the car long. And if you do break in, you'll get your ass bit by my bull dog!