You could pick up a superMID from Matt, which is what I use on my crx. You'll prolly have inaccurate instantaneous but you ought to be able to dial in the long term fuel trim. I don't really mind it being inaccurate, relative performance is all that really matters.
I was reading a thread about the SuperMid. It looks like it needs two connections? One to an injector and one to a speed sensor? The injector is no problem for me, but I believe a Festiva speedo uses a cable to drive it and it doesn't have cruise control. So I'm not sure a SuperMid would work for me? Any other alternatives besides converting over to the electronics from an Aspire and then run a ScanGauge (to much work for me)?
"If the engine ain't running it ain't using gas!"