Front Speaker in Lexus RX. Midbass or Component?

My dad's 2004 Lexus RX330 has a blown front speaker.
It's the fancy Mark Levinson Audio system. The front speaker in question is 6x9.
(http://www.lexuspartsnow.com/components/2004-lexus-rx330~speaker-86-02-2227.html (Factory Lexus Parts), #4 in the diagram)

My question is, because the replacement part is so expensive, I wanted to buy a cheaper 6x9. Just 1, not a pair, if it can be helped...
Am I looking for just any 6x9 speaker? or is it specifically a midbass driver or something? because There are many other front speakers, like tweeters and midrange.

Thank you for any help!

probably a midbass, hard to tell. Anything replacement wise will be overpriced by like 500%, I would think you will need one with similiar performance. Any way to tell what the actual specs are ?

I tried quickly researching, i cannot easily find the specifications to that speaker.

For the moment being, we are thinking of buying a cheap conversion plate to be able to use my old 6.5" component speaker from my junked civic. However, I'm not too sure if the Mark Levinson soundsystem needs special notice of its wiring, and I don't know the resistance necessary, incase its not 4ohms.

if you have a multimeter, checking the impedance is easy - set it to resistance, the voice coil will read about 75% of the rating. So a 4 ohm speaker normally reads about 3.2 ohms DC resistnce.