I will try to answer your questions, best I can...The opening for the Vibe stereo is a DIN+ 1/2 oversize..meaning, you have room for an ISO/DIN stereo and a pocket. Sorry...but you can only run your RIO if you put it in the dash... Unless you want to put a secondary stereo say...in the armrest.For the Rio, yes, you will need that "thing" (otherwise called a fit-kit), to fit the RIO in the opening. You'll need the wiring harness for the RIO itself...as well as a wiring harness for the car side (I think it's Metra part 70-2003, But I could be wrong...) Also, you'll need the following:- RCA cables to go from the RIO to the amplifier. I put my amp under the driver seat since I have a changer under the passenger, the JL 300/4 amplifier fits almost perfect. - A power wire kit to feed power to the amp. You'll need something with -at least - 8 guage wire. You need to run power from the battery to the amp, as well as a ground, which can be tapped into any metal in the car.- Speaker wire, to run from the amplifier to the wiring harness for the car side (basically going from under the seat, back to behind the radio.- The amplifier. You'll probably want something like what i've got...with all your connections on the bottom of the amp, just so when you squeeze the amp in, you'll have space to actually -plug- it in.For speakers, expect to spend that $300. I'd reccomend Polk right off the bat. Get a pair of components for the front doors, and coaxials for the back. With polk, they're offering 50% off the second pair...so you're really lookin' at around $250. (See end of post for Crutchfield pricings)6.5" speakers don't handle a lot of bass. So you'll probably want something extra for thump. Doesn't have to be much... Something like a single 10" Polk/MOMO or Infinity in a sealed box with a fairly good amp is about par. You can determine this for yourself, though... Keep in mind, if you add the sub, you'll need more RCA cables, and another power kit.- Polk 6.5" db Components
http://www.crutchfield.com/cgi...avf=N - Polk 6.5" db Coaxials (Rear)
http://www.crutchfield.com/cgi...avf=N I actually have the Polk MM6 components in the front, and will probably get another set for the rear...As far as Amps...-Audiobahn A4004T - I know this'll fit under the seat...
http://www.crutchfield.com/cgi...avf=N -JL 300/4 - This is what I have for my door speakers http://www.infinitecaraudio.co...L3004 - The amp power wiring kit (with one pair of RCA)
http://www.crutchfield.com/cgi...avf=N - Second pair of RCA (need four channels, one for each speaker)
http://www.crutchfield.com/cgi...avf=N I favor Lightning Audio for the interconnects..but that's just me. (It's what's in my Vibe)I can post more pictures of any part of the install you need. If you want anything easy step-by-step, PM or IM me, and we can get more in-depth. Hope all of this helps..
2003 Vibe GT Lava"He inched his way up the corridor as if he would rather be yarding his way down it.""For a moment, nothing happened. Then, after a second or so, nothing continued to happen." - Douglas Adams...we all miss you