I installed some Infinity Kappa 62.11 6.5" speakers a few months back. Decent improvement over stock. A few weeks ago, I installed a soundstream PN2.350D amp. I don't know anything about this crap. I'm tuning it by ear. Gain on this amp shows a range of 6v-.25v. I guess I have it set at 5.5v. Closer I turn it to .25v, it get extremely loud and distorted. So, the "5.5v" is only a little off the start position. Next, crossover. It's a switch for LPF, FULL, HPF. I have it on HPF currently. The crossover dial ranges from 35-250. I "think" it's set at 80ish. Lastly, there is a bass booster dial. I upped that a hair. Barely moved it. Sounded fine in the garage. (I read that u turn down the bass and treble on the headunit, turn volume up to 70%ish and adjust amp until distortion. Turn down). Well, I went for and spin just now and noticed distortion... ughI'm tempted to get some 4ohm style 6.5" speakers instead of these 2ohm kappas. I originally bought these because the headunit required 2ohm. Now I have a amp, it doesn't matter.