the STS is the rubber string stopper that mounts behind the stabilizer and is a good addition to any bow,IMO. the TRG/SOS is a total piece of crap. avoid it if at all possible. but dont let that keep you from buying an Exile(a.k.a. Cheetah). you can get a free replacement from Martin in the form of the traditional cable guard rod n slide and even strings. the Exile is a fun bow to shoot and is extremely accurate as long as you can get used to shooting a short bow. 30-32" ata is my preference and i shoot them better than longer bows. it all depends on the person. with its 30" ata it can be a pain to get used to as its not as forgiving as a longer ata bow would be. but it has good,speed,smooth draw,quiet and accurate. not for shooting with fingers. a release is a must. hopefully your questions have been answered. welcome to the forum. post pics of your bow when you get it.
'07 HCA Iron Mace
'08 Martin Bengal
'11 Martin Exile
Bow String Depot custom threads