In a 1991 CRX:

EMPEG head unit
Alpine PXA-H600 phase processor
XTANT 3300x 3 channel amp
DEI 2365 3 way components (in kicks/doors)
NHT 1259 12" subwoofer

The Alpine is there primarily to add digital time alignment adjustment. Next project is to figure how (and if possible at all) to get a digital output of the EMPEG to avoid the DAC and ADC processes between the EMPEG and the Alpine.

For IASCA competition, I plug in a portable CD player (Sony with SPDIF output) into the Alpine (it has multiple inputs). Not ideal, but that's the only reason I ever want to play directly from a CD player.... and I didn't want to have an indash unit the other 99% of the time.

CRX Audio System