Best thing to do would be to download the 2000 factory service manual, (free) courtesy of GaryDoug:
http://www.mediafire.../?40mfgeoe4ctti
Then check your car's Service Parts label, to see what the RPO code is for your radio. The list of RPO codes for the various "entertainment systems" is on page 0-16.
Then find the schematic for the radio in your car. I suspect you have the 10-speaker system shown on pages 8-277 to 8-279. That will show you how the amplifier fits into the system. It appears the front (2) tweeters are driven from the radio, and everything else - rear (2) tweeters, front (2) and rear (2) mid-range, and (2) sub-woofers - are driven from the amplifier.
Whether you can duplicate the factory amp with an aftermarket device is not clear to me. Might just need to find a used factory amp.
1994 FIREBIRD FORMULA
FRED
381ci all-forged stroker (Callies Stealth, Oliver billet rods, BME 2618-T61 nitrous pistons) - 10.8:1 - CNC LT4 heads/intake - Comp Cams solid roller - MoTeC M48 Pro engine management - 8 LS1 coils - 58mm TB - 74#/HR injectors - 300-shot dry nitrous - TH400 - Gear Vendors 0.78:1 O/D - Strange 12-bolt - 4.11 Pro-Street gears - AS&M headers - true duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP / 800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117 MPH straight motor
https://www.firebird...9_698_32777.jpg