i have had boats in the past that had them and some that didnt... my formula engines that came out did not .. thenew ones going in im undecided? do they make a hose that is one solid peice from out drive up to themrohousing.. my last engines just had 5/8ths

You need them

Depends on what temp your oil is running at. Some do some don't need them but if you plan on running hard I would get one.

I have one and it's too small after running hard for long periods my oil is getting up to 230+. I'm running a fairly well built 524 at 5500 to 6000 rpm's at 90 mph too. Oil coolers are typically sized by horsepower, I'm running 700hp so I need a cooler large enough to pull the BTU's out that 700hp generates and transfers to the oil. I may only use 200hp at cruise so less heat, I will most likely change my current system to one that is thermostatically controlled to handle the load extremes.

I'm putting 12" x 2" on both of my engines plus the PS cooler. I came off the remote filter adapter and run a loop thru the cooler.

x2

I would not run without them.

230 isn't all that bad really , though