i persume its the oem ek9 front lip that you have , or is it aftermarket? i had a mugen one you see .
the principle will be the same tho .
What i done was .
removed my lip from the car .
put the lip on a workbench and with a mate we gently opened up the crack and applied some " Upol stronghold " its a special adhesive thats used to bond panels of cars together instead of welding .
then pressed the crack closed (some of the adhesive will ooze out but thats fine it can be sanded down ).
then keeping the crack closed i cut a bit of plastic to put on the back of the lip for added strength and stuck that on with the upol aswell .
after around 5-10 mins the adhesive was dry and was ready to sand
sand down the oozed out stuff so its smooth , prime , and paint
Done
. hope this helps .