1997 Two Door Tahoe Rebuild

[Texace]

I have had the same 1997 two door tahoe since I was in high school. I just graduated from college and now am trying to make a decision between getting a new tahoe or puting the money that I would pay on that into my old car that I never want to get rid of. Is there any way of puting the new engines of the 2008 tahoes into my 97. I like all the features and the advantage of getting close to 20 mpg. I also realize that they are completely different models and the engine would not be the only thing that would require changing (transmission, alternators, etc.) what should I do?