Speakers Sizes for '89 240???

[lightsource]

Well, I just got a stereo for my car, I couldn't stand always having earbuds while driving so I bought a Kenwood KDC-138 Stereo for $100, installed it by myself, screwed up (connected white wire to grey striped) but I got everything fixed and it sounds fine.

But the speakers aren't the greatest, I want to put some new speakers on the front doors and 2 speakers in the back hatch. But I don't know what sizes I need.

So I know nothing about audio and I want to know what kind of speakers I can get with the stereo I have.

I went on Crutchfield.com and put in my car year and make and all of that so they could narrow the search but what doesn't make any sense to me is that they say that a set of speakers is for the front door and the other set is for the side panel. Is the side panel the back of the hatch?

Thanks in advance.

[the converted]

from the sticky thread at the top....

Nissan/Infinity Speaker Sizes

[lightsource]

Thanks a bunch!