I bypassed the entire Bose system by installing Infinity components in the doors and power amps in the trunk. However, if you find the correct wiring harness between the Rio and the leads for the Bose amp it should work. My daughter has a Mustang with a Mach sound system, which is similar in layout to the Bose, and it worked fine with the proper wiring harness (which provided line outs) Since the rio only has line outs this should not be a problem.
I should also note that I intalled an 8 inch JL Audio sub in an enclosure in the passenger root well. Takes up space but sounds great (have it hooked up to separate 2 channel amp bridged into 2 ohms!)
Good luck and let me know how it works out....
btw..as noted in my groaning above i cant get rid ot the ignition whine...let me know also if you have that problem and if you managed to get rid of it!
Ed
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...One man gathers what another man spills