Hi fredk,
Yes, car audio "specs" are wildly misleading and inaccurate, especially for the in-dash head units. Power output is often quoted at 10% distortion levels in order to get bigger output numbers.
If you go to separate power amplifiers and more expensive head units that have pre-outs, you'll generally get much more complete and accurate specifications.
I'd agree with the figure of about 3.5 to perhaps 7 watts per channel maximum at a reasonable level of distortion (1% or less).
To get lots of clean power output in a car, you have to go to separate power amplifiers. With off-shore manufacturing, those are much less expensive now than they used to be.
Regards,
Alan
