The 5901 is awesome, I have the 5902 which is the 5901 brain with a different keyfob. Its nice having awesome range. I too have the proximity sensor, its nice to know when people walk by my van, it it covers the inside well. If its not set right it will drive you nuts, but thats why you set it right. I also wait for a door trigger or glass break, those are about 100% when it comes to a break in, it doesn't lie, if that sensor is tripped you better run out there full silent is nice too as people don't care if a siren is going off, but the thief will not expect for someone to be coming out to the car plus you can bypass the proximity sensor if your at a store or something, but its worth leaving on, makes people think your car is smart !
is the key fob worth an extra $110