In my limited research (new to this forum and the Versa), the ECU and cluster are tyed together. Now you will need to mod the dash to fit the sentra cluster.
It sound as though you'll spend a lot of money no mater the direction you take.
I suggest (and this is a proven method), get you hands on a low milage mr18 engine. Forget the boltons for now and build up the donor in your own time and your own cost.
Order the MR20 crank from the parts store and compare it to the MR18 crank. Chances are its just lighter, or it may only be the crank pulley thats lighter. Possible saving money there.
If you want a bigger bore engine, have the donor bored professionally (even if you don't think it needs it, IT DOES). Have it sleeved!!!! This will insure your block can take most anything you bolt onto it.
Look this message is getting too large. Engine swaps can be as difficult or as easy as you wish. Log and short of it 'you will have no need to mod your vehicle for the sake of an engine'.
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