451m in 01 Durango

I installed a clifford matrix (sidewinder 6500) with a 451m to control the door locks in a 2001 durango, now I am having intermittent starting problems (vehicle always starts, intermittently needs to crank for 3-5 seconds)when manually starting or remote starting....I think it could be related to the factory security/ignition....but not sure.....I dont want to think the alarm is causing the problem, but the problem arose about a month after installing the alarm.  I have checked everything, had it in to dodge service, they are getting no error codes...the only thing I havent done is removed the alarm/remote start completely

1.  Did I really need to use a 451 or could I have used the neg outputs along with relays, diodes and correct resistors to lock /unlock the doors?  What is the 451m doing that the alarm couldnt?

2.  If i lock a door with the key, the factory security arms, as soon as I disarm the matrix alarm, doors unlock and the security light goes out, but I have unhooked the factory alarm disarm wire....is it turning off the security through the 451 unlock output?  Could it be messing up the factory security?

3. Techsoft mentions connections to be made for factory arm and disarm (which is the same wire-just needs to see different resistences), and states that the disarm will unlock the doors with a double pulse....does the vehicle need to see a factory security arm and disarm?  Do I need to hook these wires up?

4.  The truck uses the gray key, so I have a 555u installed, but even with the 555u removed, I still experience the problem.

This might sound dumb, but to check resistances on the resistors I am using, all i need to do is hold a dmm to each side of the resistor...correct?

Thanks in advance!

Viper,

Thanks alot for your reply! I appreciate you touching on each angle for me. I probably jumped the gun last night, but  I went ahead and removed the alarm/remote start completely...going to see if it continues to act up.....if it doesnt then the cause is obvious...if it continues to give me problems, then I can take it to the dealership----accepting no excuses about it being the alarm/remote start. 

I know they sentry key works off a resistence in the key, which tells the ignition its ok to start, could having the relay pack for the remote start or any of the wires attatched in the ignition harness cause increase resistence---which would through off this security device?

Thanks

-Cy