I had one on my 5-speed Jeep (a remote start not the one that the OP has linked to) and it was fine. You need to purchase a remote start intended for a manual transmission and there are several more wires necessary to safely use it.I have a follow up question...do people put these on manuals? That means leaving the egine out of gear and trusting the emergency brakes. Risky? How does one get around the clutch down issue?
Besides the normal wiring you will also need to wire in your emergency brake, and door sensors (dome light). To run the automatic start you first need to arm it by releasing the brake pedal, having the emergency brake on, and the engine running. At this point you press the button for a bit and it flashes the lights to let you know it is armed. You are now ready to remove the key. Turning the key off and pulling it out does not shut off the engine, and instead the car continues to run until you open and close the door (this is where the door sensors come in). Once your door is closed the car shuts off and the system is armed but will become disarmed if any of the doors open, somehow the brake is depressed, or the ebrake is released.
It sounds like quite a bit but most of that is just remembering not to immediately shut off the car and every other step is something you do anyway so it only takes a second, and in a properly wired system there should be no possible way that the transmission can be accidentally placed in gear.