The factory intake is a 3 peice unit, plenum (top), runners (middle), and ports (bottom). Guessing the best way is still going to be some form of extrude hone.
BTW with only very mild mods this car has run a 15.83s 1/4 at Milan, though the main purpose is autox/road course.
I will be using the 3.4V6 out of the early 4th gen F-bodys wich is the exact same block except for more bore & stroke. The only thing missing is the FWD starter bolt holes. Using my modified intake set, accessories, and water pump it is basicly a bolt in.
I hope to be in the 180+crank hp area, which should be quite easy.
Just need to find some where to get the intake opened up to support the 3.4L.