Can I change my 04 Mazda 6s (3.0L V6) from FWD to AWD like the Mazdaspeed 6?

There's two ways to answer this question.

1. Anything can be done with intensive modification and fabrication. The problem is, converting a fwd car such as the Mazda 6 to all-wheel drive would incur considerable expense. If you used Mazdaspeed 6 parts, it would *still* require a lot of fabrication, and if you're not doing it yourself, it will cost a considerable amount of money. I cannot give you an exact figure because a job like this is far too complex.

2. There's no such thing as "too much" power to the front wheels. Having just driven a 303-horsepower V8 Chevrolet Impala, which is also front-wheel drive, it really rather depends on the platform. Even my 1994 Ford Taurus SHO, which also had 220 horsepower going through the front wheels, handled its power very well.

Therefore, I do not recommended the swap. Your best bet is to modify the front suspension to quell the torque steer if that's what is bothering you. Some mods that quell torque steer include:

* limited-slip differential (torque-sensing, like a Quaife)
* equal length half-shafts
* strut tower brace
* keep both hands on the wheel

edit: The last time I went to the local racetrack... I saw many front-wheel drive cars run 13-second 1/4 mile times. They seemed to go down the track just fine.

I would have to tell you that changing that is gonna be terribly expensive...
You need a new transmission to start.
And possibly a new motor.
And even then it might not be possible.
My suggestion is talk to a mazda dealer first and see if it can be done, you can't simply assume because the mazdaspeed has it.
If you can acutaly do this it will cost north of $8000 probably higher!