All I remember is looking at the stickers and some had the sub and some didn't. I made sure mine did. It was a no charge option.
You aren't missing much. The sub fills in the stock setup just fine. It's no 450watt/channel PSB Stratus Gold 30hz wall shaking system, but it works with what is in the car.
It's a free option, what does one expect. It's not bad it's not good. I wouldn't buy it considering that it was a free option. I have a Basslink in my garage that is better, just don't want to lose floor space. That is why the stock sub is agood setup.
IMO, you would be better off building a aftermarket that fits on the jack side of the trunk and put the jack with the tire. Get it nicely molded and flush. That would stomp the stock setup and give you what you want. Stock setup is not for bass heads. It does do rock/classical/jazz etc pretty good though. it fills in. Anyone saying it a pos 1) doesn't have the HU matched with sub, 2) destoyed it already or 3) wants more than it was meant to put out.
The dude who said "can't hear my cd's" is smoking crack, unless the 2002 models came with a headphone setup for speakers.
IMO, forget the stock sub and put something aftermarket in.