Its easy if you can do the wiring yourself. The wiring is the only time consuming part. But the engine will bolt right up to the tranny. I just did a 3400 swap (same engine basically) and its great. I had no mech experience before. it will get better economy than your old 2.8 as well as have a very noticable power bump. my 3400 on getrag will beat my budies 04 wrx non sti to 60ish by a good amount. he starts playing catch up after that. the only other challenging part besides wiring is fabing up a dogbone mount. the 3100 will even bolt to the original 2.8 motor mount. you can get all the wiring diagrams from
http://www.gmtuners.com/ its Ryan Hess's website who is a member here.
edit: oh and you would have to do some exhaust work. I bet it would be possible to incorperate most of the 2.8's plumbing if you needed too though. I just ran a short cat out the single collector on the manifold that points towards the back of the car to a T and out both sides. it was 180 bucks to have a shop do it for me (I supplied the cat)
I was getting over 35 mpg with my 3400 on the getrag, I bet if your engine is in good shape you could get better than that(.3 liters less displacement)
plus the engine is lighter than the 2.8 cause the aluminum heads and smaller starter
I say go for it, ur engine is free and the 2.8 is dead, it will be an upgrade in reliability, fuel economy, weight, power, and keep that nice 60 degree v6 growl
[This message has been edited by LZeppelin513 (edited 06-23-2008).]
