Alright so i have 2 sundown 10's. one is an sa, the other is an e series (no i didnt buy them brand new like this. i got both of em from a friend for $150 for both an they were practically brand new. not even fully broken in yet) I am very impressed with these subs. They are INSANELY loud. im running them on a hifonics gladiator 1400 watt amp at 1 ohm. everything in and outside my trucks rattles like crazy an as soon as i turn it up my rearview mirror folds down. but a friend of mine has 1 rockford p3 12 on a bazooka 400 watt amp an while his is not nearly as loud as mine, it feels as if its gonna rip your chest apart and mine feels nothing like this. Why is that? is it the size of the woofer or the box? they are both ported but mine i built myself an i will be honest, its pretty shi**y. lol. his is professionally built tho an if im not mistaken i think its a t-line box. any input is greatly appreciated!! thanks. i just want mine to rip my chest apart too! haha