sct mirror shift and collimation

I've read the posts and reviews of the SCT crayford type focusers, and I'm tempted to get one, even though I'm not (yet) doing any CCD imaging.
But what I haven't heard addressed is the effect of mirror shift on collimation... Is that just too insignificant to be any kind of an issue?
Thanks.

----------------Steve.

I asked the same question last summer. Never did get a real straightforward answer, but the overall gist was "not enough to worry about." True? Well, it's on my test program for this spring.