this is definitely an opinionated response. i worked in car audio for 8 years so hopefully the information is valid. lol
If you're running stock speakers off of a cheap pyle deck and 2 12" woofers you're going to run into some problems hearing the highs with all of that bass. Also keep in mind that subaru's are typically meant to be lightweight and therefore their sound deadening properties are limited. You will need a lot of dynamat for 2 12"s to eliminate all of the rattles.
now for hook up.
pyle 60x2 will be hooked up deck power to the front speakers. hooking up the fronts and rears in parallel could blow out your deck if it's not stable down to that ohm load. also 60x2 from a pyle is more like 20x2 in reality. if the pyle has rca outputs then you will hook up the sub amp to woofer preferably and if not rear.
one thought would be to run one woofer instead of 2. sell your extra woofer and invest in a 4 channel amp. you will still have plenty of bass unless you are aiming for truck talk. your highs will be sufficient to compete with the single 12 and you will save a bunch of space in your trunk. then all you have to worry about is rattles.