i have lexus tail conversion... water comes in with heavy rain.. my trunk is completed gutted.. but do they sell any kind of sealer i can spray behind the tail or on the inside?

 

you'd be better off buying a tube of silicone sealant and going in around the back of your tail lights with it to seal them properly. If you want to see where they're leaking back there just crawl in the hatch and have a buddy spray the back of your car with the hose.