erm, re-used oil pump should be fine, certainly no worse than an aftermarket replacement.
T04b from where? not an ebay jobbie, won't last, not seen one do 400-430bhp, look at a gt 3071/76r or a T38.
HO inlet will need work for end feed injectors, unless you've got side feeds for it.
piper springs, get in touch with devil developments instead, seem to have better springs available.
lots of oil for lots of early changes too