Component/Amp question

well, i am very happy to help you out since I just build up my interior speaker/amp, but still, best way I can say is to go around listen whatever your ears like the most.  I go with inifinity kappa 60.5cs comp set, and they do got good reputation and quality there worth the money you spend (I got them around 130 shipped).  Rather than listen to them at store, I did research online b4 I made the decision.  But I wouldn't tell you that they are a must because everyone's taste is different.  However, those infinity kappa 60.5cs has very good and clean mid/highs for me and for most people saying out there.  The lows might not be enough compared with subs, but after I listen others about the filter setting on amp(read the other thread I just posted, very helpful), the lows is pretty much enought matching with high/mids for "me".  All I can say is one word, "cleanness on highs/mids/lows but not "overkill".  The amp I got is alpine mrv-f340, also with an alpine 9831 hu.  The amp is not a very powerful amp, but sure is enough for your inside speakers providing "cleaness sq" matching with hu for my front/rear.  When I was doing the research, the other comp speaker set alpine type Rs is also strongly recommended, but I went with infinity eventually because I probably got more reviews about them by that time.  The amp I got is about 250 shipped, don't get yourself in hurry, look around first and make the decision that you won't regret for is the most important!  Also, if you are chaning the comp set and amp, there's whole bunch work you need to do such as changing/running speaker/amp wires because factory wires is just not enough to support.  Trust me, they take much time/effort if you want them build nicely!

hopefully my experiance can help.

i've got a 91' buick, and in the rear i have 6.5 coaxial kickers (65 rms), and 5 1/4 PG Ti Elites.
Although the elites are great, and the sound is very clean, my rears seem to be alot more loud. it could be the placement of the speakers, where the rears bounce off the rear window and to the front, and my 5 1/4's stay within the front area of the car and dont sound as loud as maybe they would if placed in the back.

But if you want to go for more sound, i would stick 6.5's in the front as well as the back, 6.5's will probably beable to handle the low freq's better than 5 1/4's, and in any case, your 4x6 wont have the same quality as either size as mentioned above.

as for amp selection, im satisfied with the 50x4 im putting to my speakers, but in my case, i have 300watt Ti Elites, that could maybe get a bit louder if given 200watts even. so (2) 2ch amps may have been a better option, but honestly, 50watts is enough to make my ears sore after 30mins of listening at highest volume w/o distortion.

6.5 fronts & Rears & 4ch 50watt amp should be a good setup, you lack slight flexibility in having 2 amps to work with, but i dont think thats a big deal.
Just make sure your rears, if they are still stock, can handle 50watts, no sense in getting an amp that pushes much less than that, just so your stock rears dont blow.

i'll stop my rambling

budget details would be nice.

What you want to pay, for speakers, amp
overall budget too

Go with the largest size possible up front.  You don't want all the bass coming from the back of the vehicle.  I would seriously consider the Adire Koda component set.  They are known for great quality strong midbass for the price.  Also check out the other popular 6.5" component sets (quart, focal, diamond, infinity, etc.)

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New Project: 2003 Pathfinder