I have a '95 850 turbo wagon and I am planning on making some simple upgrades to the audio system. I want to keep it on the cheap side, and i already have some parts. I have a little car audio experience in the basics. I've swapped out a few head units and replaced speakers, but I have never messed with car amps or subs before.

What i have so far:

-2 New Pioneer TS-A1304C 5 1/4" speakers

-Alpine head unit (from a friend)

-2 8" jbl subs in a slim box (100watt 4 ohm)

I've read that the doors can usually fit 5 1/4" speakers, and if they need any modifications that its minimal. So replacing those and the head unit should be pretty easy.

Now to the part i'm not so sure about,
I only have 2 door speakers to put in, I was planning on replacing the front door ones and leaving the rear ones in. Would this cause any problems?

I also don't know what kind of amp i should get, brand or power-wise.

Any feedback would be greatly appreciated, as I do not know much about this and I hope im not doing anything wrong yet.

 

Well let me share what I have done to date on my 97 850R wagon;
Pioneer AVIC -Z1 double din nav
Infiniti Kappa 2way 5.25 front doors
MBQuart tweeters in dash
Infiniti kappa 6.5 mid bass in rear doors
Infiniti Kappa 3" in rear pillars
2 Zapco 360-4 4channel amplifiers
1 Alpine Bass Line 10" sub in a 1 cubic ft sealed box (soon to be 2 10's in a fiberglass box)

 

Here's the problem you will run into. All speakers need to have the same oHM rating. That being 4ohm impedance output from either the HU or the Amp you may buy.Your front pioneers are 4 OHM(dual cone i presume), you can't leave the OEM teeters in because they are 8 OHM. Same goes for the rear door speakers unless they are 4 OHM OEM. But then again, stock OEM rears are like a 13-25 Watt RMS speaker. Your head unit alone most likely puts out 20-25 RMS… they will blow the rears out if they are a 13WATT RMS speaker. You can pull them and get the serial number off of the magnet. the data is online. Secondly with a Headunit alone theres no crossover coming from a Aftermarket HU t feed those dash tweeters. Now about the amp. You can't buy an amp stronger than the total RMS power handling capabilities of this pioneers so you have to find out their power rating too. The total AMP RMS rating per channel should either match the pioneer top RMS capabilities or be slightly less. i.e. 75-85 RMS x 2 or 4 channel AMP for say 85 watt RMS speakers.
Put component( separate mid/woofer with satellite tweeter) for your fronts . Like original OEM setup. Perhaps you can throw the pioneers in the rear doors if they are strong enough for an amp you want to buy. I put 5.25 Component Kappa Infinity 50.9 in the front doors, their tweeter in the OEM spot(i pried off the OEM tweeters off their stock base and glued in the component speakers then fitted the original tweeter cradle back in the OEM spot. Im a little up in the air about the rear doors right now but i think 6.5 Infinity kappa 60.9 may fit in the rear spot or may try to fit another set of Infinity Components 50.9 in the OEM plastic casing that fit in the rear doors. ( i have already pried the glued in OEM's out of their casings) Ill put those teeters for the rear speakers in the OEM rear pillar spot.

I purchased an infinity 475A amp 75RMS x 4. BTW won all these at auction on ebay dirt cheap as factory direct refurbished units.. The amp was won at $99. The speakers were won at $77. The speakers list for like $180. not sure what list on the amp is. All come with Infinity warranty

or you can run the two fronts bridged and just add an amp

hope this helps