What is the maximum boost pressure that a stock LS-2 can handle without making any changes to the ECM?

Most basic supercharger kits come with some kind of programer.If a speed shop instals it for you they will most likely tune it.

I'll guess 1lb.
We can start a pool and use your motor to find out. :lol:

What is the maximum boost pressure that a stock LS-2 can handle without making any changes to the ECM?

Trying to find out how much boost your car can "handle" untuned is a great way to destroy it. You might as well start adding some nitromethane to your gas tank and see how much of that the engine can handle untuned...
The car's MAP sensor maxes out at 15PSI absolute. That is about 0.3 pounds of boost over atmospheric. The MAF will see added air mass but since the PCM doesn't know that it is coming in under pressure you will run lean and at high timing and it will detonate into destruction.

How can the MAF sensor only handle an extra .3 lbs. of boost over atmospheric when there are cars out there running at least 6lbs. of boost. The reason I"m asking is because I've seen advertisements saying " bolt on turbo/supercharger kit with no modifications". Would this be with no mechanical mods to the engine for low boost but still needing an ECM tune?

How can the MAF sensor only handle an extra .3 lbs. of boost over atmospheric when there are cars out there running at least 6lbs. of boost. The reason I"m asking is because I've seen advertisements saying " bolt on turbo/supercharger kit with no modifications". Would this be with no mechanical mods to the engine for low boost but still needing an ECM tune?

Yes that 6lbs of boost requires the ecm to be tuned or destroy your motor.The bolt on supercharger your talking about comes with a hand held programer like a diablo predator with a preloaded tune to download to your car.

How can the MAF sensor only handle an extra .3 lbs. of boost over atmospheric when there are cars out there running at least 6lbs. of boost. The reason I"m asking is because I've seen advertisements saying " bolt on turbo/supercharger kit with no modifications". Would this be with no mechanical mods to the engine for low boost but still needing an ECM tune?

Bingo. No modifications to the engine; they usually come with a handheld tuner that reflashes your PCM through the OBD-2 port.
Also I said the MAP can only handle another 0.3lbs of boost. Your MAF can handle about 550HP worth of airflow, but without the PCM being calibrated for it, you WILL get detonation.

Ok, I got it. I guess I'll go Ebay my BDS blower now. Just kidding!

Thanks!