Yep the Sprint engine and other running gear bits are very different to the std ED XR8.
Per above, also add 24lbs injectors, different extractors (limiting but they are different), different ECU mappings, other things for the sprint include, close ratio gear box, quick stearing rack, different suspension mounting points etc.
165/170/185 kw E-series engines use E7 heads.
EB GT/ED Sprint use GT40 heads.
AU use GT40P heads.
I'm fairly sure the EL GT and FBT use GT40 heads as well.
165/170kw E-series have HO manifolds.
EB GT and EL GT use the GT40 upper manifold.
ED Sprint has the Cobra upper, which is pretty much a cast version of the GT40.
FBT, 185kw EL and AU use the Explorer upper.
GT40, Cobra and Explorer manifolds share the same lower manifold.