I have a similar ghia project... I had a 1990 mustang
2.3 turbo swap that a tree had fallen on, so like you I started looking for a new home for my engine.
Bought a 1957 Ghia that someone had a "pinto beans" engine swap. It had a 2.0l ford in it and a early falcon radiator mounted up front, where the spare tire would normally be with an electric fan and a home-made shroud that went from the radiator to the gas tank. It had hard lines (approx 1 1/4" ran to the rear. It had the esslinger flywheel and adaptor plate. It had a long tube header, a modified cam cover, dual Delorto carbs and a magneto setup. The rear lid (hood) had a hole cut in the apex of the downward curve to clear the cam gear and box fabbed over the hole with a Porsche type spoiler to cover the whole thing. So basically all done except the engine was shot. The previous owner had put corvette air shocks to help offset the extra rear weight. The battery was moved forward and under the rear seat on the passenger side. A roll bar was welded through the floor to help with stiffness. The body was also welded to the pan. The rear sheet metal had all been cut out from the engine back and pullies barely cleared the rear lid. I did put a new roll pan behind the motor to clean up the looks but I made it so that it bolts out for easy engine removal. The crank pully clears that bit of sheet metal by just a hair.
So, to make a short story long, I had found a retired 2.0l ford dirt track race engine used as a backup and was able to get it cheap. Decided to put this into the car to work out other issues while planning my 2.3 turbo swap. The 2.0 I put in the car has had some serious head work, my old 351c 4v would be envious of these ports. I would guess it makes somewhere between 170 - 200 hp (probably closer to the 170 mark).
So, the vw starter won't turn this thing over, probably won't be a problem with the 2.3 as this 2.0 has a lot of compression. Had to get a high torque starter. First time I had this fired up, I spent most of the time fixing minor annoyances, oil pan gasket leak was an easy fix as this thing is just hanging out in space. Water pump was shot, again an easy fix. I finally got all the basic issues sorted, bleeding the air out of that much cooling lines took a while. By this time Winter had set in (last year) and there was snow on the ground, but since I finally had the thing running well enough to drive I couldn't resist taking it for a spin. After warming up and taking a few spins around the block I was sitting on an uphill incline in about 2" of slush. I revved it up to about 2500, found my point of clutch friction and went into what I thought would be a soft snowy burnout of sorts but instead the thing found pavement, hooked up and lifted the front of the car dragging the rear drivers corner which fortunately was just exhaust. I realized at this point that some addition stiffening was needed to keep the engine from torquing the car around. So, I kept my foot out of it from that point until I could figure a way to sort my suspension.
As soon as the weather was a bit warmer I took it for a drive on the highway to find out if it could make the 15min trip back and forth to work. That first trip on the highway was a white knuckled, terrifying experience and not in a a good way. Below 50 it felt like it handled really well but once at highway speed it was all I could do to keep it in my lane. It swung from one side of the lane to the other. The only thing I can compare it to would be a tank slapper scenario on a bike.
Ok, so I did some studying to find out the cause of this malody.
It would appear that the car didn't like the extra weight out back. the VW engine weighs around 270lbs complete the 2.0l around 320 or so, but this one has no accessories and the battery had been relocated and a lot of sheet metal had been removed so I don't think it's really that far off. I mention the because the weight of the 2.3 with turbo is somewhere around 370+lbs so you will be adding 100lbs to the very tail of the car. on a car that only weighs a little over 2000lbs to begin with, this is significant. Also of note the 2.3 is extremely top heavy compared to the flat 4 that comes in the ghia which only amplifies the problem.
To combat all these issues, I first off added a Kafer bar. this is a bar that connects across the top of the rear shock towers like a strut but then has triangulated bars that tie from each side of this bar down to the frame horn essentially connecting all the most flexible parts of the car together. This totally removed any twisting resulting from the engine. but the car still didn't handle very well. I set up the front beam so I could adjust the front height of the car up and down a it and got rid of the air shocks which weren't really valved right or had the correct travel for the ghia and put in some vw shocks that had over load springs that you could adjust like a motorcycle rear spring. The new rear shocks caused the car to sit to high in the back which caused the suspension to jack and the car kept trying to swap ends and was more dangerous than ever on the highway. I eventually ended up with KY Gas-Adjust shocks that seem to be stiff enough to deal with the extra rear weight without being to stiff to function. I also installed a midmount brace for transmission because I had torn the front transmission mount and that had generated some new up and down motion on the motor. Finally the car felt safe to drive up to about 70 but still a it skittish after that. I feel an air dam is needed to keep the front from raising as airspeed increases.
Another problem to be over come is the stock VW trans-axle is really only good for about 200 hp. and by the time you get it all tied down so there is no twisting in the rear, transmits quite a bit of racket to the interior of the car. This thing was geared for a top speed of 70 and as such, with the tallest tires I can fit on this car, I'm still turning more than 3000 rpm on the highway. It really needs, what the VW crowd refers to as a highway flier trans-axle that has a much taller top gear (lower numerically). The cost of a new transmission built to hold 300hp with a friendlier highway gear is more expensive than I have been able to justify as yet.
Then there is cooling issues. Running at 3000+rpm for any length of time in summer has been hard to keep cool. There is not a very large opening in the front of this car for cool air and even worse is that the trunk space is sealed up a bit too much for get warm air evacuation. You could luver the hood but I'm personally not a big fan, I'm going to try and remove some more sheet metal from the spare tire well, but there is only so much there as it buts up against the gas tank.
So, all that to say, the obstacles I see in the project are..
1. Cooling, radiator and lines...
2. Bracing the rear as the 2.3 will torque the pan. weld the pan to the frame, kafer bar is a must (beware not all kafer bars are made equal, do your research)and I would recommend the mid-mount tranny brace.
3. Ballast the front to compensate for added rear weight. I am thinking of moving my battery up there.
4. Trans-axle. The stock one is on borrowed time when using with a 2.3 turbo. If your Ghia has independent rear suspension (It should be a swing axle if 62), know that the axles and CV joints are a known weak area.
5. Prepare to either run without a rear lid (hood) or be ready to make some major modifications to cover the new engine. The cam pully will definitely not clear. The cam cover will need the front oil filler spout removed and the hole welded shut and move it to the rear. I also suspect that the upper intake will hit the lid. even if using a later short one. There isn't enough room to route intake tubing in front of the engine or rear. It will have to go over or under. There is space either on the left or right for a small intercooler but again, piping will be an issue.
After all this, I still can't get my car to handle well at highway speeds but below 50 it's like a slot car and it can get to 60 faster than than my wife's 01 cobra. It gets more attention than anything else I own. It's a blast stoplight to stop light.
I don't want to discourage you from your project, just wanted to help you know what your getting into and hopefully ad-void some of the pitfalls I have hit along the way. (seriously don't get on it till you have a kafer and a mid-mount brace)
If I can offer any help, just let me know, I would be glad offer any advice I can but I'm just a shade tree bum stumbling around in the dark myself. This german stuff is all new to me, but couldn't be simpler to work on.