You don't know enough about the "rebuild" to invest money in it. This is a BIGGY!

As you already know, you can rebuild your existing engine w/o needing a new one (unless catastrophic failure occurs).

So, I'd say pass. Also, if switching to a whole, new motor, I'd be inclinded to look at the V8 conversions being discussed in the modifications forum. If gas were an issue, the newer, direct injection technology would provide you with something more economical.

Or, there's the 5-spd option....

Lots to think about!