Car Audio Confusion

Im just after buying a set of two 300W kenwood 6x9 speakers to install myself in the parcel tray of my car. The problem is my current stereo operates at about 160W.. So im wondering is an amp essential? And if so, are they expensive, difficult to install?

Thanks for any help

The power ratings on headunits are ILS ratings (if lightning strikes and overpowers the power supply). They typically put out about 15-18 watts RMS of REAL power. An outboard amp is not essential but often makes it sound much better.

Cool thanks, i think ill try amp free for the first while and see how it goes