The merc 700sci uses the same water pump as a 500/525 bravo boat. The intercooler feed is t’d off the ps cooler.

I used a thru-hull pickup on my Advantage cat. It can be mounted pretty much anywhere that you can get to the bottom of the boat and be in the water at all speeds. I believe it was 1" npt thread. I ran a -16 line into the cooler and a pair of -8 lines out that dumped on the drive. It would make about 10psi at planing speeds and around 25psi at 100mph. I don't think you will get anywhere near enough water from a drive shower pickup and they cause their own problems with prop cavitation and such.

they are also closed loop, if I wasent supplying the motor with water too, id go that route

why not run a two stage sea pump and dump it into the exhaust some how

think the bravo will be able to pull up enough water to support that?

How big are your fittings on your IC? Like mentioned, procharger tees into the water from pump BUT they only feed IC with a 1/2" od fittings or so fitting as in 1/2" hose w like 3/8ths threads. Might not be enough for your requirements

Im running two stage pumps on my whipple 525's..........-16 to the engine and -12 to the IC works great been running it for two years now, Im running IMCO lowers but you should be fine with the dual pickups

3/4' fittings on the cooler so run a -10 or -12 line
i heard the imco has larger(?) picks ups on it

worse case i try and still have to drill holes

I was in the same boat when I was plumbing but went with teague marine pickup both for engine cooling and IC. Picked up the ones with AN fittings so it ties in with all my other plumbing.
https://cimg5.ibsrv.net/gimg/www.off...0b8e5eafb.jpeg
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https://cimg4.ibsrv.net/gimg/www.off...b8f99ac54.jpeg

Ran the cooler for my procharger off the bravo pump, DWP lower, and dumped out the side. Never had any weak flow issues