Actually you have it easier AND cheaper to turbo than the 420a. The 4g64 (your engine) is very similar in many aspects to the 4g63t (gst/gsx engine). Therefore, you could technically pick up all the stock gst turbo components (junkyards or classifieds) and almost bolt them directly up to your engine. There's a whole website actually which takes you through a step by step process and gives you the entire list of parts you'd need. Plus, when all is said and done, you've got yourself a 2.4L turbo.