A good 2 or 3-way will do you just fine. 4-ways, 5-ways, in a single unit car speaker are more hype than anything else IMO.
If you don't want to add an external amp to your system, I'd recommend getting speakers that are rated as close to your stereo's RMS power rating as possible. Your stereo is rated at 4 X 17W RMS. The lowest rating I've seen on 6X9s lately is 35W. These Boston Acoustics are one example. I just installed them in my '95XLE.
http://www.crutchfield.com/App/Produ...i=065S95&tp=91
I'm not pushing the Boston Acoustics. I'm just pushing the RMS rating factor. I've seen many cases where expensive 60-100W RMS speakers were installed with a 15-20W stereo, and they sound awful because they're so underpowered. Then the person has to install an external amp to get the sound they thought theyd get just with the speakers.
IMO a good rule of thumb would be to look for speakers where the high end of the RMS rating is no more than double the RMS rating of your amp. In this case 17W X 2 = 34W, so a 35W RMS speaker would be about as close as you'll get in a 6X9.
Jensen and other manufacturers make 35-40W 6X9s, but you have to search a little to find them. Everybody promotes their higher power speakers because that's where the market is, and perhaps becuase they hope to sell you an amp to go with them.