can somebody explain the differences in the models? from what i know - t2000 - small circle head t3000 - small circle head w crossbar t4000 - small circle head w crossbar and dampener on handle? t5000 - was it made? tx6000 - what does x stand for? head looks more oval, is it larger? string spacing denser in middle... also the steel tubing has different shape. looks thicker and stiffer? mostly wondering about tx6000, if this is a standard size head? looks larger.. personallly i think the 3000 was best one tho havent tried 4000. 2000 was good too. thought 6000 was maybe lacked feel and stiffer?