Hey guys, I was wondering which is better: A 5 Channel Amp (50 x 4 @2 ohms Front & Rear, 300 x 1 @ 2 Ohms Sub) I'm looking at an "MTX Blue Thunder Pro 400X5 (http://www.mtxaudio.com/caraudio/archive/pro400x5.cfm) or is it better to have an amp running front & rear, and a separate amp running the sub.
Any thoughts would help alot!!!

Pick out your speakers first, then choose an amp that meets the specs of the speakers. If this 5 channel amp fills what you need then it would be good.

There is nothing really wrong with a 5 channel amp but I'd prefer a 4 channel and a mono because you have more options if you want to add in another sub later.

I already have these in the doors:Alpine 5x7's (http://www.carreview.com/Speakers/Alpine,SPS-570A/PRD_145683_1805crx.aspx) I am planning on getting this sub:Alpine Sub (http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=13849) in a bandpass box.
I'm a newbie when it comes to stuff like this so bear with me!

Your amp will not work well - first the amp is 25 watts x4 into a 4 ohm load or 50 watts x 4 into a 2 ohm load, the sub channel is 100 watts into 4 ohms or 200 watts into 2 ohms. This is all from the MTX site.

Your sub is dual 2 ohm so you can wire it for either 1 or 4 ohms, at 4 ohms the sub only get 100 watts (not enough)and at 1 ohm the amp is not stable.

For the speakers you really want something close to 40 watts RMS at 4 ohms.

This is what i'd get for amps if you want to stick with the same speakers;
4 Channel Amp - MTX 404
http://www.cardomain.com/item/MTX404
For the sub get the dual 4 ohm version, wire in parallel for a 2 ohm load then use a 300 watt RMS amp - I like MTX so I'll suggest a MTX 311D or a 421D, the 421D is more then you need but it will run cooler.
http://www.cardomain.com/shoplist~b~MTX+Audio~t~Subwoofer+Mono+Amps

Hope this helps, I think you will have trouble finding a 5 Channel amp that does everything well. One last thing - have you heard the sub in a bandpass box, personally I hate the sound of them in a SUV or hatchback.

well your mids and high's don't do 2 ohm so that amp really only puts out like 35x4 probably