Surprisingly good bass system - on the cheap
I'm not going to claim I have a competition bass system or anything, it'* just that I find it annoying to do all the wiring and cost to buy an amp, amp install kit, install the amp, wire it into to the stock harness and battery, and buy subs and a box.
So what I've done is simply first upgrade all the speakers with some cheap aftermarket speakers off Ebay (front 6.5" components for the front, and new 6x9s in the rear). That upgrade alone, with the stock head unit, made it sound alot better. The new 6x9s with that big trunk hit pretty well. But overall not a super great system.
So then, I connected the speaker wire for the right rear 6x9 into a single crossover. The tweeter lead goes to the right rear 6X9, and the woofer lead goes to a $30 12" bass tube I bought years ago from Fry'* Eelectronics All this powered by the head unit. So basically I have $110 invested total (six new speakers were $80, and bass tube $30).
When I turned it all on, it was amazing how well even radio stations sounded with the low rumble of the 12" complementing the three way 6x9s and the components up front. I was a bit surprised because I didn't think the head unit alone would have enough power to push the bass tube, but it does. I love the finished sound since the bass isn't super overpowering like you'll get with an amp and a box, but the tube is still getting enough power to add alot of a ton of bass punch to radio stations and cd'* that you can't get from the 6x9s alone.
If I was in high school, I wouldn't think this system was powerful enough. But I love how the finished sound is blended, with great bass. The bass tube sucks off enough power from the 6x9s to completely get rid of the rear shelf rattle/resonance you get powering those speakers normally. It also eliminates the sound phenomenon with the stock speaker locations where the bass sounds like it is coming from the rear. With the inexpensive tube, the bass just fills the cabin so you can't tell where it'* coming from.
Just thought I'd add this post to show that you don't need to buy $500-$2000 worth of electronics to get a much improved pretty fun bass system. It all depends what you're looking for too. It doesn't rattle doors, but if the doors are open and you're 50 feet away, you're like damn where is that bass coming from. I will admit I'm squeaking out every available watt from of the stock head unit, but it'* been up to the task so far without dimming its lights. They aren't that bad of a unit. I would normally upgrade to an aftermarket head unit, but my last 3 vehicles I put one in and I'm tired of that aftermarket look.