they're supposedly 6x8/5x7's all around (keep in mind they'll both mount the same) it's considered ford/mazda, so alpine 5x7's will mount in the exact same holes as a rockford 6x8's.. so don't think you need one or the other
I put in 6 1/2 components in my front, and 5x7's in the rear.. if you want a good sounding system go with components up front IF you have an amp to power them, or just a good set of coax's.. IE kicker s80's, rockford power 6x8s, alpine type-r 5x7's.. the stock amp or an aftermarket deck will power them alright....
last year I had alpine type-x components in the front, alpine type-r 5x7's in the rear, alpine (xx) amp only did 75 rms to each channel (underpowered the type-x components).. 2 ultimate T2 12" in sealed boxes, ultimate t3100d amp, PG 1 farad cap
this year i have ultimate 6 1/2 t2 components up front, kicker s80s in the rear, alpine 75rms 4channel, alpine mrd1000, 12" kicker l5 ported box... just sold it to my friend, so ill be getting something new in july.
now.. with respect to the head unit
Alpine head unit - try for an older model 9853
be more concerned over the amp you get, than the speakers. you can make alright speakers sound alot better with a good amp, than a ****ty amp with amazing speakers.
dynamat, brownbread, or any of the sound deadeners actually make your car quiter.. but it will sound better - dynamat is expensive, brownbread is very cheap and is virtually the same in quality. the main parts in the mustang that rattle..
in the rear the cardboard top that holds your speaker grills, that rattles on the other plastic panels and the glass.. I just stuck random things, ie: black gloves, black cloth, just to act as a dampener between the contact points.
in the trunk, the metal "layers" will vibrate where the bolts are, so tighten all your bolts, nuts, etc in the back. the spoiler will vibrate to no end, along with your license plate.
with a loud car the vibrations you hear, are almost always coming from the trunk, so dont jump to the concluson that its in the passenger compartment.
by the way, that rear amp/speaker deck is a total waste of space and heavier than hell.
it weighs about 40 pounds, most of that is the plastic its made out of I swear. it also takes up about 6 inches of trunk height near the back of the trunk for possible sub usage.
I just have my 2 speakers mounted on the metal with brown bread to stop the high frequency rattling that would ensue... and with that I can fit sub boxes
in mustangs you're guaranteed to almost always need custom boxes.
in regards to your ipod, almost all decks come with AUX inputs, so you'd just get the ipod output (phono type deal) to rca.. the downside to that, is it has to go in the back of the deck....alpine's come with AI-NET which require like a $20 cable, and that connects directly to your ipod (that input is on the front of the deck)
Try to get matching sets, as it's usually balanced.... you won't have to worry about under or over powering, or not having good pre-outs for the amp you purchased.
if you have the money, go with alpine.. (NOT THEIR CHEAP DECKS! THEY LACK ON FEATURES WHICH WILL HURT SOUND QUALITY)
If you're looking for a cheap deck with good SQ and features, get a sony fx7710/fx7715. it has 4v preouts, 6 or 8 way equalizer, with treble/bass/sub settings. it looks good, and it works nicely. I actually enjoyed that deck more than my current alpine 9851 (grr) and it was also $200 cheaper.
most car audio stores.. just give them a price u want to pay. most car audio equipment is generally marked up twice the cost. so say for a 400 sub, say ull pay like 275, and most likely they'll do it.. because theyre still making 30-75 on cost, and it's helping their sales numbers.
and i'm not sure what size they are. 
:SNSign:
