Well so I guess most people installed a magnetic switch of some sort ON THE SHIFTER LINKAGE to detect neutral.
Well my car is RWD and it has no linkage, just a shifter going directly into the transmission.
So what are my option in this case?
Another thing I'm looking at is install a hall effect sensor of some sort on the wheel / driveshaft so that if the car does lunch forward it would generate ground pulses and effectively abort the remote start right away. (works the same as the hood switch) but this should really be a final safety measure.
I've seen a circuit explained in a Viper installation manual that explains this situation. Many older GM cars have a mechanical neutral safety switch built into the steering column. The ignition switch won't engage the starter if the column isn't in park or neutral. But for the column to be shifted out of park, the key has to be in the ignition. The viper manual explains a circuit that connects to the keysense wire of the ignition key cylinder(the wire that triggers the warning buzzer when you leave your keys in the ignition). But you didnt say what king of car you have. From your screenname, I'm guessing you might have an Eclipse. Are you installing a remote start on a manual transmission RWD car?
My best advice to you is to try using the parking brake. Test your parking barke. Se if it will hold the car still when it is engaged and you put the car in gear. If the car moves, have this fixed. Make sure that the e-brake is capable of holding the car still. After that, wire up a circuit that connects to the e-brake so that the remote start will ONLY work when the e-brake is engaged. I've seen a few remote starters specifically made for manuals that have this type of circuit made into the remote start.