type 44 speaker impedance?

[David Michael]

Folks,

I am trying to track down the occasional buzzing from the rear speakers on
my 90 200QA (non-Bose). Does anyone know if the speakers have "normal"
impedance and can be replaced with any 4ohm speakers? The head unit is an
Alpine plumbed into the stock amp through a  scosche line-output converter
(for the rears). I was thinking of either bypassing the stock amp and
installing  regular 2 way speakers (ie-removing the line output
converter and wiring  from the head unit directly to 5.25" speakers) or
replacing the stock speakers with component speakers still powered by the
stock amp/crossover unit.

Whatever I do, I want to re-use the stock wiring so I can just jumper
everything together as needed without removing consoles etc (that may be a
problem, since the wiring from the radio to the amp/crossover only has L+,
R+ ,Gr,  and I am not sure if I can combine grounds from the Alpine unit
without blowing up the output stages).

Ideas?

Thanks!

Dave
90 200 QA, 230K
98 M3/4 101k