Not really sure why it´s called "Special Trooper", because it´s pretty much the same items included with the regular sets. The 2009 sets, however, with working parachute like the "Soldier Force VI Peace Force Paratrooper" or the abseiling " Soldier Force VI Action Figure Playset - Captain Deadeye", have a lot more special to it. Then again, all of these are supposed to be Special Ops troopers, in their own way...
Figure: "Frogman Deepdive". For more detail on this figure, refer to "Soldier Force V Coast Patrol Playset".Figure: "Captain Red A-6" Original green helmet. For more detail on this figure, refer to "Soldier Force IV P-40 Combat Fighter Playset".
Most, if not all 12 "Soldier Force Series IV" line figures became available single-carded after 2001. Similar move used with themes like "Police vs Bad Guyz" and "Wild Quest". Figures ranging from US$1.5 to US$2.9 around Europe. Later, all their -official- themes had ranges of choice from 1-figure to 6-figure packs. And so did their TRU counterparts "Elite Operations" and "True Heroes".