You only need the official patch from Microprose to run ie 1.08 version. The iBeta and Realism patch fix some AI problems, missile and other weapons performance become more realistic (You can evade missile). The official 1.08 version has a bug that is kind of like a cheat, if you bomb an enemy airfield, that airfield will remain unoperational forever (before the patch, bombing airfields does not reduce enemy air traffic at all). With the iBeta patch or any other realism patch, the airfield needs a certain time to repair (depends on the damage you or your wing have done). That's just one of bug fix. There are all kinds of add-on to for look of the cockpit.