1. In all honesty, not really anything on Ryda that would match that price. If you want to spend more than yeah, but for >$150...not really.
2. Yeah mate it will sound HEAPS better. I remember when I got my first sound system, tiny 4-channel amp with 40wrms going to some Pioneer door speakers, and 160wrms going to a Pioneer sub. Man I was blown away couldn't believe it. I gave that sub such a flogging for the first week, I look back now and wonder how I didn't kill it. Now the setup I've got you looking at has 80wrms going to each door speaker and 230wrms going to the sub (which is probably twice what that old fusion sub of yours was getting).
3. OK rough guide.
* Bolt amp in boot
* Run 2 sets of RCAs to boot. The back of your H/U has 2 pairs, one for front and one for rear, obviously front will be for doors and rears will be for sub.
* While your at the back of the H/U find the power wire, this obviously only turns on when the key is in the ignition, splice that (solider it and wrap in electrical tape), and run this next to the RCA down the left side of car. This is the REM cable, usually plugs between positive and negative terminal on amp. It makes sure the amp only turns on when car is on, otherwise it would drain you battery when car is off.
* While back seat is up, unbolt one of the seatbelt bolt and sand paint away, place negative power cable ring under bolt and bolt back down, then plug into amp.
* Install speakers in door, put the crossovers in behind the vent things on end of dash, held in by 3 screws. Install tweeters in factory dash position, demister plate just lifts up. Either use factory cable or lay own/supplied cable from crossover to speaker. Putting own is not hard, and good insurance. You may need to cut back out of speaker pod as new speakers will be deeper, just cut back off with a knife, no problems with this, just only cut as much as you need to.
*Run new speaker cable down each side of car for each door speaker, to the crossovers.
*Speakers done
*Now last thing is the power cable from amp. Lay cable from battery, through the engine bay, through the clutch grommet (This is just below and to the passenger side of the brake booster), behind carpet to drivers kick panel, and run underneath drivers side scuff panel (run power cable and RCAs on opposite side of car). Under back seat, into boot and hook up to amp.
Now tune the amp.
* First set Channels 1 and 2 (these are the door speakers) to HPF and set to about 80hz
* Now set the gain on the amp (very important to do it right). Get the gain to lowest, play a 'normal' song on the H/U at a 'normal' volume (not on max), and slowly raise the gain until you can hear ANY distortion, then turn it back a little bit.
*DONE, have a carton and life is good.