just make sure when you drill not to crack the plastic. i used a 1'' countersink bit and went slow and came out perfect, with a regular bit it will grab and then crack..... bad news. i have done this in 5 of my trucks without a problem. and if you have the rubber grommet style strobes they really dont need to be on a flat surface to seal, but if they are the screw in type i would use some silicone or even hot glue works.