2001 Dodge Intrepid, Which Remote Starter?

Often times, the range listed on a specific R/S unit is under "ideal situations".  Warm weather with no interference and inline of sight.  As you mentioned, many variables come into play and all reduce the range.  Systems with FM frequencies give much better range than the budget priced AM frequency systems.  Of course the price goes up quickly with the longer range units. 

That's a good question.  With some systems / manufacturers, they pretty much state it in the model number ( adding FM ).  With others, you have to dig a little deeper.  Compustar marks the Antenna with AM or FM.  If you can get the FCC ID number off the back of the remote transmitter, you can look the specs up.     http://transition.fcc.gov/oet/ea/fccid/    I don't think there is a list that just spells it out for you.  It's basically brand and installer experience.

A possible "general rule of thumb" is AM systems never exceed 3,000 feet of "advertised" range and FM systems usually start at 3,000 feet. 

Here is a link to the completed 2001 Intrepid / Python 5303P install by sportsfreaked with photo's and plenty of detailed info :

https://www.the12volt.com/installbay/file.asp?ID=1317