TEXT:  The Joy Of "4" 
  Branson Hagerty (Blackjack's Shadowrun Page http://shadowrun.html.com/users/blackjack/) Posted June 17, 1996
  One of my main goals in life, aside from becoming incredibly rich and buying Canada, is to create a nice
  set of balanced Shadowrun rules. This usually has taken the form of little tweaks and twists here and
  there which have, over many years, added up to a system of gamemastering in which it is very rare that a
  PC, or NPC for that matter, enters into a situation in which the are certain to get their ass kicked. An
  element that has been instrumental in achieving this balance is the replacement of virtually all opposed
  success tests with the simple target of 4. 
  Take spell casting, for example. Under the traditional rule structure a mage tossing a powerbolt with a
  rating of 8 would be certain to waste anybody with a body of 5. I've been meaning to sit down and
  calculate the actual odds of success for each individual but I keep remembering that I possess no
  mathematical ability. In any case, anybody who's played knows the result. Just moments ago in order to
  test my theory I rolled some dice in order to play out the scenario and, using my fingers and toes, counted
  up a total of 13 success for the mage over the target after five contests. Then I did the same thing, instead
  using the unresisted target of 4 for both tests. After five contests the mage still came out on top, as would
  be expected, but this time he only achieved 7 net success over the target. 
  So what does this mean? It usually means the players will absolutely love the gamemaster for introducing
  the use of unresisted tests until such time as they become all powerful and want to more easily kick butt.
  Well, tough shit. In the beginning this rule helps protect the runners from NPCs and later in the game it
  helps protect NPCs from runners. A balance is achieved. And, most importantly, it makes the game much
  more fun. How many times, either as a player or a gamemaster, have you had to roll your four dice
  against a target of something like nine knowing full well that there's a better chance of the CEO of
  Renreku sending you a Christmas card than of achieving any hopeful amount of success? A target of four
  is actually reachable and although you probably won't get out of the situation unscathed you won't get
  out of it with a lone success and a monosword stuck through your head either. 
  Oh, yeah, all modifiers still apply. 
  
SOURCE: textdata/thevault/Shadowrun [multi]/EXTRAS/Alernate Rules/RULEjoyoffour.pdf