1999 Mercury 225 EFI lower unit

[Drew12]

Hello, I have a 99 Mercury 225 EFI and the lower unit just went out on me yesterday. Don't know what happened, I was on my why back to the ramp when all of a sudden the over temp alarm went off and the motor died. The motor still runs fine but won't go into gear. By the time I got back to the ramp and got it out the water I found a dime size hole on the right side of the lower unit by the bottom water inlet hole. Safe to say the lower unit is toast. I'am currently in the dilemma of getting a Mercury lower unit or an aftermarket. I was needing to find the spline count for the 20" shaft and thoughts on the whole oem or aftermarket deal. The serial number for the motor is 0G937877. All thoughts and help is very appreciated, thanks.