https://www.bestbuy.com/site/pac-amp...?skuId=6254906
This is a must have if you have JBL, otherwise you'll need to deal with a summing device and a DSP to get around awful OEM EQ curves.
Rockford Fosgate DSR1 and Maestro is an even better solution but more expensive. There are also a few amplifiers that are Maestro compatible.
iDatalink - Maestro - Search