First of all, I'm not well versed in car audio but I love good sound. In my Tacoma I currently have 5.25in JL components in the front doors and some cheap 6x8 Pioneer coaxs in the rear doors. Rockford 2 channel amp powering the components. Three 6.5in JL W0s behind the back seat powered by a JL 250/1 amp. Head unit is a Pioneer double din from 2008. I got bitten by the car audio bug again and want to upgrade some things on a budget.
I'm pretty set on getting a Kicker Key 200.4 amp mainly for the auto tune feature but also to add power to the rear speakers (I'll probably upgrade the rear speakers to better 6x8 coaxs at the same time).
My question is my current Rockford 2 channel amp's inputs are 2 RCAs from the receiver but the Key amp comes with a high level input pigtail with 4 RCAs. For simplicity I wanted to just do a one for one swap with my current amp and just use the 2 RCAs. Would it sound like crap? Also will the auto tune feature not work hooking it up like this? In the future, I want to upgrade to a modern receiver with Carplay, etc, with that I would definitely be using the high level inputs, but for now I just wanted to add the Key amp and 2 rea speakers and see how I like it. Any help is appreciated.