my friend did the same as you, he replaced the fuel injector relays, ECU and a couple fuses

 

You make no mention of the fuses in the crew compartment. Have you made sure all those are good in particular the one named ENGINE? If you don't have a digital meter that you know how to use, its nearly impossible to help you. Parts swapping might get you there someday though. Simple, cheap digital ohm meters are available at any Radio Shack for less than twenty five bucks. There is also a manual with schematics available at http://www.iluvmyrx7.com you'd be mostly interested in the FUEL section and the schematics. Anyone can follow the schematics. Its not high tech.

The ENGINE fuse in the crew compartment is just as important as any fuse under the hood. Theres another one there that has to be in working order....I forget which one right now. Only takes ten minutes to see if they are all good.

 

not to be an *** or anything, but HOW THE HELL DO YOU MANAGE TO HOOK UP THE BATTERY BACKWARDS? IT ONLY FITS ONE WAY!
the positave and negative terminals are different sizes, you can only hook the positave cable to the postiave side and the negative cable to the negative side, they just won't fit any other way unless you pound them on or something...

 

Its quite easy to switch the terminal connectors when they are both cheap aftermarket parts. As far as the dmm, that's not a problem, I install car audio and security for a living. All the fuses are great. any more ideas would be great. How would i go about testing the fuel injection relay's?
Thanks,