I received bad news yesterday. I have a 1999 TW 200. I was told a valve droppedand there is a nick on the cylinder wall. I'm looking at $1000 for the repairs. There are currently 2 engines available on ebay. One is from a 2003 and the other from a 1988. My question. Will the 2 optional engines bolt right on to my 99? Will there be any modifications needed? Or should i rebuild what i have? The bike has 8000 miles.I'm not to good at this kind of stuff and want it done right. With all of these options I have in mind that it's value (running) is $800. What should I do? Did i mention that i love this bike.