I believe the T.S mean expensive but no fuctionality of the equipments. In the tight area, u need a wde lens for a group shots, but do u need a expensive one wif a red ring to get a good shots?
I do shoot fast action sport before wif a normal tele len( sigma 70-300) and a not so great camera (40D), not really work of a pro but can record the moments nicely wif a good position. nowadays most camera body have a shutter speed that can freeze sport action juz fine and most sports event have good lightings. I believe if u give me a super tele L lens and a ID mkiV i cant come out wif a much better photos.