Exactly...

If it was a non turbo 1g dsm you could make it turbo easy if you have all the parts you need. Its just bolting it all up, and adding a few wires here and there considering it already has a 4g63 but the 420a motor isnt as easy to peddle with turbo whether it be swaps or boosting the 420a.. But if anything just try that and turbo the 420a... Or just go buy a gsx which would be the only good option in my opinion.