Agreed, you would definitely know if you had the mach system. Here is more info on it. Mach 460 Information
Now that being said, if you dont have the mach system you would be much better off going out and getting an entire new system. The stock system just has the head unit for an amp and is garbage.
I would recommend a good set of 2 way speakers: Infinity Reference/Kappa, Alpine, Polk, Boston Acoustics.
A new head unit: Alpine, Pioneer, (some) Kenwood.
A 4 channel amplifier: Anything name brand. Pioneer, Kenwood, Alpine, Infinity, Rockford, Kicker.
Subwoofer system: Kenwood, Kicker, Alpine, Rockford Fosgate.
You can use all of the factory wiring if you dont get the 4 channel amp. I would highly recommend it however.