if its leaking oil from the dipstick tube I would start by replacing the seal for that. Most manufactures allow a certain amount of oil to disappear through oil consumption. When I worked n VWs it was 1 quart per 750 miles... So even if you adding 1 or 2 quarts between oil change intervals, is saving a 3 dollar quart of oil going to justify a rebuild?
my guess would be that your exhaust tubing was covered in oil from an external leak, not an internal wear issue.
Modifying cars is retarded. Buy a bike instead.