Hi, I did an engine swap on my 1.8TS a couple of months back, my first one. Unfortunately I don't know how hard it is to swap leaving the box in place as I pulled it out as one lump.
However I didn't find it too bad a job. I removed the battery tray, radiator and air filter box to give a little more space and I had the exhaust manifold off and dropped the air con pump. The inlet manifold and other ancillaries all stayed on.
It didn’t take long to disconnect all the water, fuel, vacuum pipes, electrics etc.. I disconnected the power steering at the rack end.
My main hold up was the drive shaft bolts on the near side they were very tight and I rounded two of them! Despite them being clean and using a good quality (Snap-on) allen key socket.
You have to remove the mounts from the block / gearbox as well as the chassis, which you need a large ribe bit for, no 12 I think.
Once done the engine swung out at an angle off side first (high). It is tight and watch out for the aircon pipes on the near side.
On engine swap re-aligning the gear box was easy with both units out the car.
As Haynes would say refitting is the reverse of removal. Lining up the mounts was fairly straight forward and easier than I thought it was going to be.
Whilst the engine is out don’t forget to check your brake pipes.
Hope that helps