The main reason besides obvious overheating that the heads/ gaskets develop problems is the stretching of the head bolts. Same problem on the Neon 2.2. If you convert to ARP studs, no worries.

Another thing on overheating is the corrosion build up in the cooling system after 100km. $65 US gets a boil out for the rad, another $35 for the heater core. Refresh the corrosion inhibiter every 2 years and again, no worries.

Oil builds up in the intercooler from the vent into air filter. Boil out, relocate the vent after the intercooler if its a problem.

The motor you have is at least as reliable as any gas motor. Parts for anything that's 15 years old are going to take time to find whether its gas or diesel. Swapping in a gas motor won't improve your odds.