Getting my first sub

Like the topic states I am going to purchase my first sub becuase i finally have enough money   After much looking here and on the web i think im gonna go with.

Alpine SWR-1021D Type R (10" 300 RMS 2 Ohm)

 ...and power it with...

 Alpine MRP-M350 (350 RMS Mono amp)

I dont want anything to be damaged by choosing the wrong stuff....would these work together? 

If i wanted to get another sub later...would having one new and one used together sound bad?

I will want to add some small speakers for mids and highs later...probally SPS-170A ... my deck's amp puts out about 20-25 RMS i think, is that too low to sound proportional with my sub?

Thx for any advise you have!

Looks like your off to a good start.  That dual 2 ohm sub will help you get the most out of your amp, and later if you add a second you can wire it to 2ohms mono then to. 

Why don’t you get a 12" though?  I would recommend one sub over two, for simplicity.  12's also go a bit lower.  What do you like to listen to?  What kind of car is it? 

I would not recommend coaxial, get components. 

ALL decks are to weak to provide good sound for all but the smallest and low end (crappiest) speakers.  For good sound get a separate amp.  Try to match up the rms power of the amp to the RMS power of your speakers.  Even if the amp you get is 35 rms per channel, it will sound far better then the 25 watts from the deck.  In the past I had demonstrated this with a 4x25 Pioneer component amp I had, it would outshine any deck by a mile.  You could use a 4 channel amp to run the sub and your full range speakers.

Your plan looks fine really, nothing wrong with it for a starter system.  What’s you head unit model?  If I had to advise you this is what I would say:  Get a 12" not the two 10's.  Use the money you will save getting one sub instead of two, combine that with the money you would have spent on the coaxials and get components.  You will probably even save money this way, about 100 American by my guess.  Get the mono amp above, or get a 4 channel amp to run it all.  I did not figure in a box for the sub because you did not mention it above.  Good luck, let us know how it goes.

Thx for the input!

Im gonna stick with one ten because i dont want it too boomy... i listen to classic rock and rap    The car is a Nissan Sentra and the head unit is a Sony MP80 (I know y'all hate sony but this head unit is way cool)

So components over coaxial?  Would you recomend getting 4 or would 2 be enough?  Its gonna be a while before i can afford these anyway....but what amp would be good?  Should i stick with Alpine or is it silly to make all my speakers the same brand?

Two things i thought of while delivering pizza tonight....One; It gets real hot here in Phoenix.  In the middle of summer my trunk hits 130-140F .. Can the sub hold up to that heat? Should i add an external fan to the amp?  Also my car has a small stock alternator... I think it is 70 amps.... will this be enough?

Thx again!