Please don't kill me...

What motor/ trans combo could I put into it to improve daily 40 mile roundtrip commute (in traffic) mpg, modern reliability, hopefully better acceleration and speed, carefree 300 mile roadtrios, etc.?

In traffic... are more gears (over drive) really going to help mpg in traffic enough to justify the cost?

I don't know much about turbos, but what about turbo-ing (new word?) the slant?