Remote starts can be installed in manuals, but recommend against it. If you leave the car in gear and try to start it with the remote start it will buck forward, and if it does start you could hit objects/people in friont of the car.
I had it on a manual 91 Maxima once. I watched it lurch across the top deck of parking garage. It was hilarious, but could be dangerous.
Doug Thorley Tri-Y LT/cat back, Ported TB, Halltech CAI, Pedders sways, endlinks, Drop Springs, Tuned by TandTPerformance 371HP/383TQ