It will work either way. If you're doing a complete harness replacement, leave it uncut, fit it into the firewall, thread the new harness through, and go about your rewiring. Cutting the grommet just makes it possible to replace it without disconnecting the whole harness. A little brake fluid on the grommet will make it easier to install, and it won't hurt the rubber like oil would.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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