I think that the Ecotec would be a better choice for the 4, there must be a reason that GM used them for their sponsored land speed cars. Of course I'm kinda partial to them because of ther reasons..
I think it was a political decision. The ecotec is the base engine in just about every car GM sells right now. Well a lot of them anyway.
Pro/cons. The cool thing about ecotec is that you can get forged internals from the turbo variant. Also direct injection, dual VVT, and cast aluminum intake manifolds.
On the con side, you'll need all that tech to overcome a 45% displacement deficiency to the 2.9l. 2.9 has bigger ports/valves to match.
I was just thinking how cool it would be to put a 3.7 into a Solstice.
