What is a good engine to swap with? on 2000 Mitsubishi Diamante

I was thinking a MiVEC. Maybe a later Diamante model like Vr-x. The stock engine has 186,000+ miles on it. Would you suggest swapping or waiting until it completely fails or wears out? I get p0401 code and p0510.

thats your choice but you might get another yr or two out of this motor those codes are egr and tps related no cause to repl engine
That was my first option, but I would like to do heavy modifications to it. Would a new turbocharger go well with the engine it has? being all used and old. or what would be best to increase the horsepower...engine wise?
i think you are pretty much stuck with what you have in the car already