When I was breaking in my 3.4, my only real observation was that the 3.4 was the engine that the Fiero should have come with, right out of the box.
That was before I pulled it back out to build it up.
(First rule of hotrodding... If "more" is enough, then "too much" is just right.)
What makes it "worth the cost" is if your 2.8 has given up the ghost.
It's not really any more expensive to rebuild and swap in a 3.4 than it is to rebuild a 2.8.
And any mods that will work for a 2.8 will work even better for a 3.4.
[This message has been edited by Raydar (edited 10-05-2013).]