Are you talking aboot a twin engine job? Or just shifting the drivetrain to the rear?
It has been my dream to make a mid-engine KL capri for many years now, I just haven't been able to throw the time & money at it. I have two shell candidates & most of the donor parts, at least the stuff that doesn't have to be made. And the tools needed for fabrication.
But the KL swap isn't trivial, front or mid-engine.
It sure would be a lot easier to just stick with a stock drivetrain & smack it into the rear of the car. No axle issues, the wiring is already correct & just needs extended to fit what's already there. Adapting a set of front hubs to work in the rear of the car would take some work but it's been done in other mid-rear conversions, and that's how the Pontiac Fieros were initially built. Compared to swapping in a totally different engine, it is "simple"
It is tempting, I've thought about it a lot.
On one hand - moving the engine is enough work by itself.
But on the other hand - if you're going through the work, why not make it worthwhile?
One could shift a stock engine & swap it later. But how much would need to be re-done?
Either way, from what I have gathered, a mid-rear swapped Capri will likely not be a great performance car on the track and may be a bit touchy or even a tad dangerous on the roads. But it would be unique and given the right choice of differential it would be a cool burnout machine.