mach audio similar aftermarket speakers

I cant seem to find aftermarket speakers that perform and sound as good as my wife's old Mach Audio Mustang. She had a subwoofer at the bottom of the door and the highs at the top of the door. The space of the door created a nice bass. I am trying to recreate that on my Dodge Ram 1500 but cant find speakers that sound that low. Someone mentioned the Infinity Kappa Perfect 5.25 but I am not sure.

Also if I get a component I read that all you need is a 2-channel mono amp to push them since the crossover will take care of everything else. I have one channel available on my amp for my single sub setup. Can I split that one channel into two so 150 watts RMS goes into 75RMS into each component?

Thanks everyone.

Ok, I found some subwoofers that are 5.25". They run at 4ohms 100RMS so they say. If I have an Xplode 55W x4 @ 4ohms amp, will that be enough for the subs or do I have to get a 100RMS. I read the "little power" sticky where this guy messed up a sub running less power to it.

I have been running 14w from my pioneer stereo to a 55w rms pioneer speaker for over 7 years. Does that mean my speaker is messed up?

Thanks

that should be enough power, but i don't think you are going to get the bass you are expecting from such a small speaker.  it won' hurt to try, but may prove to be a waste of your money.  do they need a box? if so, can u fit it in your door?  most subwoofers require a solid enclosure-use manufacturers specs as a starting point.  I don't know how much sound you are expecting from them, but in my experiences with subwoofers and their loudness; to some extent, size matters (surface area)

"I have been running 14w from my pioneer stereo to a 55w rms pioneer speaker for over 7 years. Does that mean my speaker is messed up?

- do the speakers sound ok?  they are probably fine.  you are only going to hurt the speakers if you are trying to push 55w rms to them from that pioneer stereo that only puts out 14w.  (understand? hopefully i worded correctly- what i mean to say is if you are overworking the stereo and clipping occurs;then you can damage speakers. 

I think I understand. You mean playing the 14w receiver at full volume so it sounds nicely distorded with clipping. I already have a single 10" sub under my bench, but I wanted to add a little more with these and maybe highs through a crossover.

Do they need a box? I dont know. Good question, most speakers say if they are air or enclosed right? I'll have to check

Thanks.