To start off I researched the devices. All key fobs are under a FCC id so I decided to hit up the FCC database and found the filings here:
https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Sum&calledFromFrame=Y&RequestTimeout=500&application_id=spKnbExGiCHJozOZmVpVNg==&fcc_id=M3N-40821302. The is all public knowledge and open source research. The most important records are the one with the RF Frequency information on them:
https://apps.fcc.gov/eas/GetApplicationAttachment.html?id=1386312
So the plan is for me to sit in my garage with my fob upstairs and try and do the following.
1.) Attempt to open the door -> send LF message out but key fob is upstairs so no one is listenting, or are they?
2.) Intercept LF message with laptop nearby -> replay message with amplification so whole house is covered, therefore the FOB should reply.
3.) Fob responds with message but car doesn't have sensitive enough antenna -> intercept message at laptop with sensitive antenna and spoof RSSI information to gain entry and start car.
I will not be going into any technical details on how to do this. 1.) Illegal 2.) I would notify FCA first of any findings as required by law. 3.) Don't want anyone elses car to be stolen.