I would suggest you read through the performance section of the FAQ. It deals with issues like this one very well.

As for suggestions, I would recommend examining and replacing all the wear items to make sure they aren't the problem, including:

- air filter
- fuel filter
- plugs

A valve tappet adjustment can make a huge difference to both performance (tightens it up) and fuel economy. Running some injector cleaner through (Techron, STP Full Fuel System Cleaner) can help.

The fuel you use can matter, since in a turbo regular or lower grades is a hinderance... at high compression (lotsa pressure, boost conditions) lower octanes burn unevenly and can preignite in the chamber. This causes knocking and predet, and the knock sensor would retard the timing (lean the mixture) to couter it. This would cause weaker performance and extended wear on your engine. Hence the reason you should only use premium (93 and up) fuel in a turbo engine. You'll also get better mileage, making the higher cost moot (at worst you come out even with a better running engine).

You also realize that boost doesn't generally kick in until 2800 rpms or so, right? Boosting on the low end (2000-2500) doesn't generally have a very dramatic effect, and will do nothing (except maybe wear the turbo) if you are in 5th on a hill, etc.

Most of the other possible problems would leave obvious symptoms; AMM would cause stumbling and major fuel economy drop, o2 would be similar, turbo would throw oil and leave a blue-black plume behind you, etc.

You might also check the fuel pressure regulator at teh rail, but I don't think that's your problem.

-rt