I have the speaker upgrade in my wrx. Before my rex I had an explorer where I had 2 JL12's and many other things. It obviously doesn’t compare to my old system but compared to most stock car systems it does sound pretty decent. The bass isn’t bad at all unless you turn it up based 20 on the volume. If you’re not the type to put big subs in the trunk like I am but want some decent bass, then I would say get them. Just go easy on that little sub under the passenger side seat.

 

Any decent speakers that you are going to want, the head unit wont be able to power. There are some speakers out there that will work but are not worth the money because the quailty will be poor because you are running them from the head unti. MY advice would be to save your money, get a new deck, get a nice 4 channel amp, and then get some speakers like:
ADS, Focal, Alpine, or Bostons. I am not a stereo god or anything but I have some knowledge about speakers and what are good brands. If you need more help about what to buy or anything just ask.

 

Let me clarify what I meant, if you want a good set of speakers, the head unit wont be able to power them. The head unit in the Subaru and all after market ones usually put out about 52x4. Which means 52 watts for each speaker. Now if you get some good speakers, which means you get some ADS's or Focal’s with separates (which means it has a tweeter that is located away from the speaker) the unit wont be able to power them. No after market deck would be able to because they need a lot of juice.

Now there are some speakers out there that will run off of the head unit. There are some alpine's and bostons that don’t need an amp to run them. IMO, it’s not worth getting these speakers that run off the deck because
1. You can’t turn them up nearly as loud
2. The quality of an amp driven speaker is 100% better in sound
3. Most speakers that run off of head units are co-axel (meaning that the tweeter and the speaker are combined), which reduces the sound quality

It all comes down to money and your preference. If your not the type of guy that likes to blast his system everyone in a while (I do it every day. Probably why I cant hear out of my right ear as well =) ) Then getting some speakers that run off the head unit will probably be fine for you. But if you are like me, then save your money and get a good deck, amp, and a nice pair of Focals
or Bostons.

Here's what is going in my Subaru WRx if you would like to know:
Sony CDX-MP80 deck (got it for free =) )
1 pair of ADS separtes
1 pair of boston acustics co-axel in the back doors
5 channel sony which is running all the door speakers
2 JL 12 w3v2 subs in a costume made box w/ a 750 watt amp running them both
sony 10 disc cd changer


I hope this helped you and anyone that has the same question.

 

Yes, good speakers need an amp and ok ones (a little better than stock can probably run off the deck).
I am not quite sure if the factory head unit can run an amp. I am not that familiar with it so I can’t help you there. If I find out I will let you know.

 

Ohh and to let all you know who been posting questions about how big of speakers people have put in. My ADS with separats up front are 6.5 and my boston acustics co-axel in the back are also 6.5. I'm am also running 4 gauge wire though out my car. I know this may sound like over kill but if you got the hook up on wire why not? Plus I'm doing this because i maybe be getting 2 JL 13.5 w7's =).

 

arent the upgraded speakers mcintosh. stock impreza speakers are clarion.

 

Actually I was very surprised how good the "up graded" system sounded. I'm not talking about the sub, I can make more bass with my farts but the speakers them selves weren’t that bad. People have been saying that they turn it up past 10 and it sounds like crap. I listen my music (rap, rock) and I have it always set between 22-26. I never go higher than 26 cuz that is when it sounds like crap to me. I have the bass set at 0 to -1 and the treble is set at 3. But compared to any other aftermarket speaker, these do lick b*lls.