[SCOTI]

I can't answer your first question because I like to use stock replacement shocks & make my mounts to work w/them (or choose a similar vehicle w/a 'better' length). The other stuff is answered in red....

Originally Posted by 72gmcshorty

Will the shock limit how low my vehicle can go when i air out my bag? (will it prevent me from bottoming out when i air out?)
Yes, it can do both if the optimum length isn't used.

I know when you put a 3" drop spring, you've dropped your truck 3 inches. When you replace the spring with a bag, how much drop do you now have...About the same. 3" drop @ ride height & more when the air is purged.