ICM started making for some rough hot starts right before it failed on me. Fuel pump is also a reasonable suspect, especially for hot start issues.

Note - if that ICM fails partially and puts down two cylinders, don't try to limp a few miles anywhere. Take it from somebody that knows better but tried anyways, it cost me a cat on top of the ICM. :gaah:

 

Problem solved!

Issue was the new MAF I had installed a few months back. Apparently, the new MAF was defective, so I had another MAF installed and eureka...no further hard starts when warm.

While attempting to troubleshoot this problem myself (I am admittedly a beginner), I was able notice the following:

-hard start when warm (vehicle sitting for 20 mins to 3 hours)
-able to start, but only after throttle input and holding at 1000-1500 rpms for a few seconds immediately after start
-rough idle for about 30 seconds following above
-on scan tool (OBD II bluetooth reader with app Dash Commander), -14% fuel trim noted (can't remember if this was ST or LT)

It appears that the hard start issue was due to the MAF being defective, and not providing the proper air into the engine on startup (mixture rich), causing the computer to attempt and subtract fuel from the mixture (negative fuel trim). Fuel trims since the new/working MAF was installed are +-5% (normal). Ideally, the fuel trims should be 0 as the computer is always attempting get the same ratio of air/fuel.

On a separate thread, I would like to provide some "baseline" data observations from my OBD II bluetooth/Dash Commander app. I would also encourage the weekend mechanic to get an OBD II wireless scanner ($20.00) and the Dash Commander app ($9.99) as these give you a ton of data to observe (HP, torque, MAF/MAP info, Fuel Trims, etc) and will likely help in trouble shooting some issues.
:beer:

 

Already provided some logs a while back

http://www.impalaforums.com/chevy-impala-7th-gen-discussion/546609-rough-idle-and-p0171-code-5.html