JARblue

Don't worry about all that. Just disconnect the negative battery terminal if you're at all concerned. I've done it on a bunch of 370Z TBs all different ways: with and without the battery connected, with and without removing TBs (o-rings looked good and didn't need replacement) and always lots of butterfly valve movement to get the back side clean, especially if you leave them installed. Never had an issue other than needing to relearn the accelerator pedal position, which is super easy.

Liberal use of the right cleaning products (MAF cleaner and Throttle Body cleaner) will be just fine. Use a stiff bristle brush to aid in the cleaning process (only on the TBs, not on the MAFs).

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