Water operation for a car can be tricky. I learned a bit about it in an Austin Countryman.
A Countryman is sort of like a Mini-Cooper (old style) but in a station wagon variety. The top of the car was about up to my rib cage... w/ 12" tires. Naturally, in Panama, where you can have 8" of standing water after a 15 minute rain, it wasn't ideal. Fortunately, it was FWD, so even when the rear end was floating, I still had some traction.
Prior to the mods, running into a rain storm could cause problems, as water streamed under the bonnet. (Cars all pulled over, since the best wipers couldn't keep up. At 45, I was nearly swept off the seat of my MC running into one of these storms.)
If you use grease on the spark plug wires, make sure it doesn't have graphite (or other conductive materials) in it. Back then, I used some silicone grease, used to insulate telephone connections. The cap and coil were sealed with bath tub caulk. It worked well.
One worry is with a hot manifold. The 'Zuki doesn't have a weak manifold (unlike the cast iron on this car) so it's fairly safe, but it can still crack... and the head is moderately strong... not as good as Detroit iron, but better than most inline 4's. Still, deflector shields aren't out of the question.
For this car, I built it in 2 pieces. The top part bolted to the underside of the hood, to the grill area. That was bolted to the lower section, which was also bolted to the pan of the car. Not much water comes through the radiator, but there can be a huge splash from under the front bumper, as water rushes in. You can see your engine temp drop 50 degrees in seconds. It doesn't help with flooding water, but can keep you from being blinded by steam under the rear of the hood.
I also sealed all the connectors. I once "lost" the engine to a short in a connector from the generator. The same connector carried current to the distributor, so it's hard to tell which connection shorted. That short killed my V-regulator. (Being British, it wasn't overly surprising. <g>)
