the engine is no more likely to pop on the street while tuning than on the dyno.
street tunes are cheaper cause you don't have to rent dyno time to data log, and they are more complete because they include all the part throttle tuning you need to make the car drivable on the street.

While you are doing the install, send your PCM to Bryan (PCM4LESS). From the time you send it to him, till the time you get it back should be less than a week. His mail order tunes are pretty damn good, used it on my heads cam stock bottom end, and on the 396 Im currently running. Both setups ran really well, and I will be seeing him for dyno tuning this year.

wheres he located? i'd love to skip the mail order if possible.

did you call Eastcoast Superchargers?

never even heard of em?

east coast supercharging is near great adventure. they mostly deal with teh corvette crowd, but they do work on LT1 and L98 f-bodies too.