Porsche Dash Speaker Install

[ralphie]

Ive gotten used to the factory audio in the car, as one would normally, and would like to make it sound better.

However, the more i read the more options there are to choose - including obviously size, then ohms, sensitivity, tweeter control and the list goes on

My question is, can i plug a 2 ohm 4" speaker into the dash where it is originally a 4 ohm output from the heas nokia 40w 4ohm output,

or

can i do something to make it work?

i fancy the idea of tweeter level control because it allows me to turn down those high frequencies that the stock system does well to tune down, and wiring several dummy speakers saw sound rather harsh and too much detail 'up there' not much 'down there'

im looking at 2 ways rather than components as components (mid range and tweeter separate) look like more hassle!

thanks in advance for any advice