I think it's also based on what's popular, and what people will pay for it.
For example, compare the price of the V-trac to the Tru-trac for sbc.
http://www.billetspecialties.com/ite...pid=802&rdir=1
http://www.billetspecialties.com/ite...id=182&pid=649
Both include all accesories, but there's over a $1000 difference in the way they're mounted.
