The graphite head gaskets are factory replacement. Down side to them is that the coolant passage being so close to the fire ring on the rear cylinders eventually deforms the gasket material and migrates too the cooling ring.
It takes time, but if you keep your coolant up to date so that corrosion doesn't occur, they can last well over 100,000 miles.
If you have the motor out it would have been a better deal to have the machine shop clean up the factory deck surface getting it even smoother. not all shops can do this, but it's worth it to find one that can. Then do the same for the heads. That'll let you be confident in running the MLS head gaskets which shouldn't have the deforming issue by the coolant port.
It's worth it to gasket match the intake side. Make sure you do the heads and the lower intake manifold.
If you have any thoughts of pulling the heads in the future, the ARP studs are a good investment but are not required if you don't plan on pulling them on purpose and are just doing a stock rebuild.