Studs only stretch along their vertical axis when you tighten them, they don't twist, same torque = greater clamping pressure.
The nuts on a stud are almost always a finer thread than those in the block which permits more precise torquing.
Torquing down a cylinder head equipped with studs feels nothing like torquing down the same cylinder head equipped with bolts, the studs feel significantly more "reassuring".
Studs are the immediate go to with any head bolted engine that has been pushed to the point of regular head gasket failures, (due to raised cylinder pressures).
IE: supercharged, turbocharged, nitrous engines.
Virtually all of those big HP diesel motorsport engines that the Yanks love, Duramax, Powerstroke, Cummins etc, have head stud conversions, because they blow head gaskets without them.
Modern diesels went to stretch bolts because they are cheaper, (again the whole "no need to re-torque scenario") not better than studs.
Head gasket failures are fairly commonplace on modern, small capacity, highly stressed diesels, I wonder why?
You won't find any cylinder head bolts on a 10,000 bhp Top Fuel engine, or an F1 engine.

I'm not trying to talk Frans into, or out of anything.
The stud enquiry was just out of general interest.
They are commercially available for pretty well any commonly modified engine (that originally came with head bolts) for a reason.
Most likely a NA engine of the Renault's vintage, (even a high performance version), won't generate high enough cylinder pressures to warrant head studs, unless there is some inherent weakness in the original design.