asafd, yes.. if I remember correctly, Trek's line up of frames is roughly as follows, from cheapest to most expensive:
Alpha SL (1000 series frames/bikes)
ZR9000 alloy (2000 series frames/bikes)
OCLV120 (5000 series frames/bikes)
OCLV110 (5900 Superlight frame)
By the way, "Low-end" doesn't at all mean that it's a poor quality frame; it's just a simpler-to-manufacture design with less exotic materials, and won't be as light/stiff/etc. as their higher end product..
e.g. the Alpha SL frames are made out of basic aluminium and machine-made in Taiwan, whereas the others are hand-made in the U.S. out of more exotic alloys or carbon fibre.
Alpha SL (1000 series frames/bikes)
ZR9000 alloy (2000 series frames/bikes)
OCLV120 (5000 series frames/bikes)
OCLV110 (5900 Superlight frame)
By the way, "Low-end" doesn't at all mean that it's a poor quality frame; it's just a simpler-to-manufacture design with less exotic materials, and won't be as light/stiff/etc. as their higher end product..
e.g. the Alpha SL frames are made out of basic aluminium and machine-made in Taiwan, whereas the others are hand-made in the U.S. out of more exotic alloys or carbon fibre.