For the coil you'll have to fab something yourself. There is a post that has pics of several different ways to mount them. Probably about 4 months old. Some guys mount it in the same place on the block. I mounted mine on the fender b/c of the materials I had to work with.
As for the cap and rotor, I doubt it will cure your water problem. Unless the cap and rotor you have now are very worn. You could always seal them with some silicone to keep the water out.
I'll try and find the pics and post the link.