Best thing to do would be to download the 2000 factory service manual, (free) courtesy of GaryDoug:
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
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