Id say go for it. Vr's are solid engines and usually wont let go unless its had some real abuse. chains and tensioners as mentioned if you can be bothered. The price of the engines now days to me makes it hardly worth the effort. If it detonates, go and buy another block for 3/4 the price and lob it back in.
most wiring problems are fairly easy to fix. Just look at the quality as to how its been done. Does it looks like its just been lashed in there or someone has actualy thought about what they are doing?