RE: Time for a rebuild?
u wont be disappointed with the os18cvr-x, its a stormer of a little motor. u will however break drivetrain components more often unless u pay particular care to the diffs (shimming) and the diff cups (cup mod or restricted ride height to solve the prob).
all the answers are on this forum, any probs - just yell, and we will set u right mate.
good luck hiding it from the missus!