I looked at both as well and purchased the Stealthbox. I bought the JL product because I know that their speakers can produce great bass (in the right enclosure), and I was certain that an 8" speaker would not be able to reach as low as a 10" speaker would.

I bought the Alpine amp that comes highly recommended and had my local professional install the amp and speaker in the right rear panel. Although I am pleased overall, I was expecting more "pounding bass." This setup, though filling the low end as it should, will not rattle any windows. My local car audio professional was very unimpressed with the system. He believed that the box was insufficient for the speaker (but it does fit nicely).

I listen to many types of music and this box does a fine job of adding some punch to my non-DSP system. Yet, if you primarily listen to rap or hip-hop and want to make an impression on the car in front of you at a stop light, neither one of these setups is what you need. You will need to come up with a custom system. If you are just looking to add punch to your system, I recommend the Stealthbox.