pairing factory remote with viper 5901

Hello everyone, my name is Dom, I have read a lot off the site over time but have never posted.  Awesome site. 

I have a 2005 Pontiac Montana SV6 with factory keyless entry and remote start.  I also have a 2003 Chevy Cavalier (manual locks) with just the alarm function hooked up professionally using the Viper 5901.   5901 will be removed by myself.

Basically I would like to use the 5901 just for the pager alarm system.  I don't care to use the 5901's remote to lock and unlock the doors, I would just like it to go off when there is shock or door open.  Do you guys think the factory and 5901 systems will conflict each other while keeping the keyless entry and factory remote start?

I'm planning the above install by just copying over how they installed it on my cavalier to my sv6 following wiring diagrams.  My professional shop suggested to ditch the factory system and install 5901 alarm and starter for $200. 

What do you guys suggest? Thanks for any advice you guys have to offer.

Well, the montana has the factory remote start and factory keyless entry already there.  I'm on a tight budget here but  I would still like the pager alarm feature from the Viper.  Will my plan work?  I know I'm not using the Viper 5901 to its full potential but the factory remote start system works fine for me.  I have yet to install a security system so I may have the wording wrong, but will wiring the 5901 just to the door triggers interfere with the BCM or mess up my Montana electrically speaking.

Maybe in the future I get the 5901 fully installed at my car audio shop, but for now, I can really use that 200 elsewhere.

I hear you guys.  So I think I should read up on how to do a proper full install myself.  I have all the tools and skills to handle the job, I will just need to read up on it.  I don't want to have to depend on the local shop if I were to change cars again.

I have been reading up on bypass modules.  I see everyone favors the iDatalink and Fortin Modules. 

The iDatalink says their products are exclusively for mobile electronics professionals and require online registration with valid business credentials to access vehicle firmware programming.  So I can't get this one..

I read up on the Fortin EVO All GM.  There is a great install guide on the website and it handles all the features my Montana has available.  It says it will operate the oem remote start in the guide.  I like how many different vehicles it works on too.  Looks like this module does not require extra hardware or special program software like the iDatalink, correct?   Any recommendations where to buy, I will see if Fortin will sell to me directly if possible