Well you can cut it off, but don't expect any warranty on the GPS antenna!
Garmin have a rubber boot arrangement on it which would keep the connection waterproof - probably hard to do at home. You could use self-amalgamating tape to make the best of it.
It's a BNC type for RG58 cable (VHF type).You can get a solder type here.
You can get twist on ones as well but wouldn't use for this. May also be able to dismantle the original one.
How well it lasts depends if your're bracket-mounting and taking it on and off every time or flushmounting with a permanent connection.