You can make the 3.4 make good power, but it won't be cheap or easy. The typical bolt ons that help on a choked up V8 won't do much for the 3.4, as the main problems are the heads, the intake manifold, and especially the small displacement. The cheapest way to make power that is ging to be noticed, is to go the nitrous route. However, the little engine is not going to appreciate that type of abuse for very long.

If you are interested, look in the v6 section on ways to modify this engine.