Exactly. I think that running in England, if you'll excuse the old "my country is better than yours" crap, would create sneakier Shadowrunners.
Think about it - with these rules in place, it's pretty damn difficult to come by the big guns. That means that all the runners are going to be under-equiped in terms of combat. The corps, though, being extra-terratorial, can ship in whatever the hell they please.
This means that to start your career as a runner you need to think about how to do things without getting into combat. Being sneaky and stealthy. I want to get my characters to think about what they are doing, rather than the old "frontal assault" style. If they are more than likely to get popped, they'll be more inclined to use their heads.
Now, once you're
in you can pinch as many guns as you want, and with a higher street index (as would be a logical extension of the avail. increasses) you could make a killing, if you'll excuse the pun.
This does, however, mean that a number of Corp tactics would have to change to reflect this... trackers in firearms? Remote explosives? At the extreme end would be biometric safeties.
You could also cap the applicable firearms skills at something lower than six.
You can use these rules anywhere, theoretically (I just use the UK because of its history of gun restriction and, well, because I'm British). They would be a perfect means to get your players thinking and performing non-violently.
Now... cyberware........