Isn’t the BMP-3 more of a side engine unit? A 1500 HP turbine is pretty big.
The BMP-3’ engine is mounted under the floor in the rear. The engine on one side, the transmission and PTO on the other. The PTO is for the hydrojets. And IIRC it’s a 500hp engine in the BMP-3, and the Russians don’t have anything more powerful than a 1,250hp turbine that’s small enough to fit a tank.