Audio question when adding a sub

I have the non JBL system in my 2015 taco. I upgraded the 6x9 and 6x5s to all kickers and a Crunch (1000w amp) to power them. I am interested in adding a 10 inch kicker sub. My question is do I need to add a second amp to power the sub? I think the answer is yes because the amp doesnt have any free spots to plug it in.

I was thinking though I could disconnect the rear speakers from the amp and power the sub and the front speakers with that. Is that possible and ok to do?

Should I just add a second amp for the new sub? Is that normal and ok also?

I dont have much audio knowledge. I do love the sound of the speakers and amp, just need dedicated bass. I listen to most genre of music but when I occasionally listen to rap, I want it to sound like I am a big balla shot calla got more hos than a golf course yo. Oops sorry about that last sentence.

Thoughts?

 

if your amp has a low pass filter for the 3&4 channels you can run a sub off them, essentially turning your 4 channel into a 3 channel amp, ive done it plenty of times myself.

looking at a few crunch amps online, i think ive found the one you might have, which would be rated at 250w rms for the sub channel. so i would look for a subwoofer in the 200-300rms range.

 

Thanks for the advice. Now to focus on a enclosure for the sub and amp.