To remove your ECU plugs you have to pinch the clips on them and then pull them out. I just had to do this to do the soft rev mod so I feel you on your question. It took me a minute to figure it out.
As far as you tank goes as long as the wiring isn't damaged I think your been fine. Just make sure you don't have any exposed wires.
I'm sure someone will chime in on this.
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