JBL System add an amp & sub

I'm wanting to replace the stock sub with a single 10" and add an amp. What's the best way to do that, I know there's the PAC Amp pro and LC7i but will the

$90 AudioControl LC2i 2 Channel Line Out Converter with AccuBASS and Subwoofer Control

LC2i also do the same thing cause it's way cheaper?

 

if you've got the factory jbl system, i believe it's easier to replace the truck

 

Check the A/V section. Several solid threads about reworking jbl there and lots of knowledgeable people willing to help.
Since you’re looking for cheaper options this definitely isn’t up your alley but oemaudio+ is the way to go. Plug n play, but the price tag isn’t for the faint of heart. You can basically rip everything out and replace it for the same price I guess