I think Josh got most of it... just going through myself trying to be complete. Given a T4, an X - 6 conversion kit, and some sort of buggy shocks, you'd need the following:
*B4 front arms
*B4 front tower
*B4 turnbuckles (all 6)
*Perhaps B4 outer hinge pins, depends on the truck you have. If its got the GT2 front end on it, the outer front hinge pins would not be long enough (they got rid of the spacer that normally goes behind the caster blocks on a B4).
*B4 CVD bones (probably should get the BK2 axles while you're already ordering stuff)
*B4 front axles (they're shorter than the truck's)
I think that about covers it.
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