The "crappy" paper cone speakers are vastly better at reproducing midrange detail then poly cones. The problem is that paper is just not strong enough oz for oz to make a good subwoofer. Factory systems rarely use more than one crossover point so you are stuck with a tweeter and a single driver to cover the rest of the spectrum. Paper means nice clear mids at the expense of the bump everyone wants.
The monsoon in my 99 regal actually sounds great but does not have enough volume for my taste. My first thought for an upgrade is a single 12" or pair of 10" subs and build passive crossovers for the factory speakers to cut the frequency somewhere around 100Hz.
If you primarily listen to rap or top 40 music, that midrange detail wont matter a lick.
Well, my stuff was all blown when I bought the car. I didnt put garbage in the car though. Kenwood execeleon components up front, Kenwood 2-ways in the rear doors, and Kenwood 3-ways in the rear deck. All have an amazing frequency response and power handling. I'm also running them amped.