well i cant say anything about the ecotec manifold, but i do have the one for the 2.4 and the quality is outstanding with it so im assuming the ecotec would probly be much better since companys seem to take more liking to the eco anyways.
but i can tell you right now a ton of ppl will say its a waste of money even though they have never used it or seen it in action, they are a very expensive piece and really... too expensive. if your into a good manifold i would say look up the air forced 4 intake for the eco. or if all your after is na performance, ask pj (daflynskwirl) about the 2.4vvt 'ho' manifold.
there has been a few posts on here about the 2.4 intake manifold for the 2.2 ecotec. there was even a recent one about a company that was selling it all as a kit.
1997 RedR - ZedR
wait we can bolt up 2.4 manifolds to our ecotecs?
http://www.jbodytuner.com
^^ The real jbody store and forums!!!!!
the 2.4 tc intake needs the tb area worked on before you can use it
ive yet to see or hear of anyone using the eco intake from venom