I installed this on
BMW 330i

Review
I went with these Hertz HX 250 sealed up in the "Performance" box by Hertz. I listen to about 95% Rock and Country so I needed something clean, tight and punchy. I noticed that this little subwoofer did a really great job! It played everything I've thrown at it very well! It's hitting those notes that I didn't know existed on some of my favourite songs that I've been listening to for years. It is really impressive! The sound is so warm and mellow, but you can feel the crisp hits in your seat back. I love the attention of these sexy build quality. The sound quality is awesome.

What I like
It's hitting those notes that I didn't know its existed.

What I do not like
Pricey as compare to other brand.

I installed this on
BMW 330Ci

Review
Installed these Hertz HX 250 woofers as my friend had recommended me to get them. Had a preview of it on his car, and I was blown away by it. They were slightly expensive for my liking, but after getting the 'sneak peak' of it on my friend's ride, I had definitely love them. Now, after 6 months of using it, I find that it was definitely worth every cent. It produces a crystal clear tone, along with excellent low toned bass with maximum pounding. It doesn't feel 'weak' as compared to some others which after some time, the vibrations and pounds coming from the woofers get weaker. Mid and high tones are delivered well, and I must say I have enjoyed these 6 months having this woofer installed in my ride.

What I like
Excellent low toned bass that pounds, along with great sounding mid and high tone delivery.

What I do not like
Expensive for any average driver's liking.