Putting the engine under the cab, in the stock location, means you have all the noise and heat and limits how low you can mount the cab.
I've seen a couple where the engine is mounted under the seats, which allows lowering the cab further, but you still have the heat and noise.
I'm not advocating the mid-engine approach, just repeating what I've been told when I asked the same questions.
I'm still gearing up and collecting parts to do two COE projects. On one I think I'll copy the under the seat approach, covering the back of the motor with an old looking in bed tool box.
On the other I'm now considering rear mounting the motor. This would be for the project I've called my COE Suburban Cargo, and mounting the motor all the way at the back using Toronado or El Dorado or GMC motorhome parts might be the best compromise to achieve what I want.
