What you must also remember is, not just any collie, as if you find a good collie with good temperament ect and its all you want, does not mean to say, its brothers and sisters are the same!
Collie's vary so much, i think its as important, to find a good strain of collie, where its ancestors can be traced for good temperament and all the good things, that go into making a good lurcher.
I have seen, from a litter of collie's, their could be 1, that is leggy, good cattle dog, calm thinker, not a yaper, quiet ect, yet its brothers and sisters, were hyper tire chasers!
A good strong, cattle dog