As far as I am aware it is illegal to put a remote start on a manual. If the car does not have a neutral safety switch I would definitely not recommend it.
I had a remote start on my manual, and all it took was for someone else to drive my car and they left it in gear. When I remote started it, it took off down a hill and parked itself between two trees. Cost me over $1000 to fix the car. I was lucky though, considering no one was hurt. If the steering wheel had not been turned, it would have drove right into a gas main for a townhouse complex.
I have also heard horror stories of people with their cars in the shop and a mechanic accidently started the car and it drove off the lift.
I am not saying it can't be done, but unless you are SURE it has a neutral safety switch, don't do it. I took mine out after my incident.