I’m new to the forum so sorry if this is not the right place to ask. I have a 2013 Silverado crew cab and I know under the backseat is my only choice without doing a custom Center console my question is what subs will really hit or single sub my budget is 1,000$ for my whole system and I will be doing all my own installation and I have all my door speakers already so I need head unit sub or subs box and amp and wiring kit and I wasn’t going to do any sound proofing just yet I know I’m asking a lot but I just really wanna know can this truck really bang with the downfiring or upfiring setup and if so any help with the box would be great 

First step is to figure out how big of a box you can fit and your limitations there.  Until then it is hard to shop.  Time to mock up what you think you can fit, then we can help make sure what you shop for does the most it can for your space.