I didn't realize how painful it will be to mount the front license plate on my pre-owned C300. There are 4 holes already drilled in the bumper but they are 10 & 3/4 inches apart and 3 inches tall. This is not the standard size for CA license plates. I'm assuming the previous owner had some mount. Any ideas on what mount to use on the curved bumper with similar dimensions so no new holes need to be drilled?