Hope you find enough room under the dash
Think there is room under dash above passenger compartment. Might put it in trunk but I'm not sure wires will reach. Will post pictures when complete.
OK. Finished installing amp. Power to battery. Ground on frame under dash. Otherwise plug and play to RS stereo. Pretty slick. Small amp mounted also under passenger dash. Pretty easy. Did have to drill into front trunk from passenger compartment to run power line to battery. Power cord under trunk carpet. Everything unseen.
Not being a real music guy I really underestimated the difference an amp would make. All sound is crisp and strong. Biggest difference is in bass output. Before I could barely hear any sound from the small tweeter speakers. Now they sing. Took the car out on the highway over 70 mph. I was wrong. It is possible to hear crisp music over 70 mph. I think before the amp was installed I was turning the volume up and just adding lots of distortion. Now I can just crank the volume with no distortion until my eardrums are about ready to burst. Pretty impressive. Obviously I cannot comment on long term reliability of the RS since I just installed it. $330 for stereo and $140 for amp. So with tax just under $500. Obviously I installed myself. Took forever but hey its a hobbie. Kind of pricey but now I have a kick A$$ stereo that looks like a 50's AM radio. This thing has so many capabilities I will never use. All I'll ever do is jump into the car with my phone in my pocket, stream music and make hands free phone calls. Right now I love it.
Congrats Phil, Glad your liking the sound...
Running a good amp with more power and wattage does not equate necessarily to more volume but it gives you more deep base notes and high notes that are just way clearer..... Good sound systems sometimes have 450watts oer channel just to handle to colour in the music.
On my RS I am thinking of adding the RS subwoofer just for more colour not for more thump thump 
Ray
Good on you Phil. I knew you'd like it better.
You've discovered what a lot of people have...a good amp and speakers can make even a cheap, crappy headunit sound great no matter the make.
I'm no audiophile but do enjoy having the pleasure of a good sounding stereo in my vehicles. The daily drivers have built-in amps for the stereos and all the 'toys' except the Cobra have good headunits, speakers and aftermarket amps.
Still there is no sounds better to the ears than the rumble of the exhaust from a well tuned, well running engine....
My IM has a Cat and 2 magnaflow mufflers, smog legal in 50 states. Not much growl. Guess I'll just listen to music.