Any intake manifold off a VW 4-cylinder crossflow, transversely mounted engine should bolt up to your VW diesel head and fit within your engine compartment, as long as it's not the kind that has fuel injectors mounting to the manifold. The diesel head sits in the same location as a gasser cylinder head and has the same intake ports and bolt pattern.
Volumetric efficiency comparison of a 1.5 liter diesel vs 1.6 liter gasser, euro GTI heron head model (same intake manifold as a A1 gasser short-runner application), taken from the VW 1.5D SAE paper:
The naturally aspirated diesel's induction system, including it's intake manifold design, plays a role in achieving the diesel's superior volumetric efficiency of 92% between 3000-4000rpm. The gasser manifold is probably tuned to allow help the motor to achieve it's volumetric efficiency peak at a higher RPM of 4500-5000RPM.
What are you and/or your dad hoping to achieve by swapping out your diesel intake manifold?
I wouldn't expect a short runner gasser manifold to give any benefit unless you plan on using very high RPMs often, and it will likely hurt power and torque at rpms below that point.
If you are looking for a cold air intake, I would recommend adding the cold air baffle and snorkel found in Rabbit automatic transmission diesel models. You could also use a TD air filter (they are thicker) for lower resistance of the air filter element, although I don't think it would noticeably benefit a naturally aspirated diesel.
If you want to really kill your torque, try swapping on a TD manifold on there. :lol: (Actually, if you were to try this, I would be really interested in hearing the results.)