You can repair or replace the amplifiers one at a time. If you're repairing the original amplifiers, you may want to do them all to avoid further circuit-board damage. There are options: repair or replace the amplifiers or get rid of the system altogether. Changing the system is costly. All components must be replaced and the wiring modified. Although the original Bose system may not be capable of extreme bass, it's a high-quality system that, once repaired, can be reliable.
If you repair the capacitors yourself, go to www.ZR1.net for instructions on a '91 amplifier capacitor replacement. It can also be used on other Corvettes.
If you prefer to have your amplifiers repaired, Sound Repair in Cocoa, Florida, (888) 615-9700, will do it for $75 with a lifetime warranty. Expect a two- to three-day turnaround. Sound Repair can also replace a circuit board damaged by electrolytic capacitor fluid.
Beware of N.O.S. (new old stock) amplifiers that are being sold as correct but have different part numbers. The amplifiers are matched units to the receiver and, in some instances, sold as correct matching units from another application, causing poor sound. The part numbers must be the same as what was removed. If the N.O.S. amplifiers are working now, how long before they have capacitor issues?