I think you better recheck when the STS came out it was for model year 2000 so they arrived in fall of 1999 not in 1998 the 9010's 9610 and such is what came out for model year 1998
The Titans came out in the fall of 1978.30 years ago.The Titan 2 in 1984.The 9400,9500,9600 in early 1989.The 9410,9510 and 9610 in the fall of 1997.The STSs in August 1999.The 60 Series in 2003.The 70 Series in 2007.I doubt you will see a bi-rotor in 2008.TOOOOOO soon after the the 9570-9870 introduction
The STSs were introduced in 1999 and the 9410,9510 and the 9610 in 1997.The years 1998 and 2000 are totally irevelant because the 50 and 10 Series were shown to dealers and farm shows befroe the turn of the year