Although kverges ran into some problems, he essentially wired in his greddy emanage ultimat piggyback ECU onto his turbo'd Lotus, and is still running strong.
So unless kverges's car is a freak of nature that will never be repeated again, I don't see why at least other piggybacks like the AEM F/IC can't be wired in if everything was done 100% right the first time around, and until somebody can source the Lotus connections in order to make harnesses. I see that they're only $400 after a
Google Product Search search. How much more is a wire job on top of that than spending $3,000 on the EFI? Although this would be best for when you go SC than NA, I don't see the downside to getting control over your car's ECU this way. As for standalones for DBW 2zz's...that'll take more than custom wiring...