I would pass up on rebuiding the 200 and purchase a new motor. It may cost a bit more but it will save you lots of heartaches down the road. Plus the fact it will be new with a warranty if anything does go wrong. I have not owned a 4 stroke but have heard lots of good things about them. They weight more but use lot less fuel. Although Merc has some new 2 stroke out that is pretty fuel efficient. I am a total Merc fan.

1-Merc
2-Honda
3-Force (which is all merc nowdays)
4-Yamaha

There are many more Merc Dealers and motors out around the world. I also have owned a Force for 12 years and have well over 6000 hours on it and have never been happier with it. 120 HP.