klr 650 advice on 1987-2000 year

[exactsound@hotmail.com]

I am in the info gathering stage on the KLR 650. What are the important differences in the years "87" to the current 2000 year. Plus- I was wondering what opinions are out there on synthetic oils and what life span can be expected out of a well maintained KLR650. 50,000 miles plus? Any other links that could answer any of these questions please send them to me. exactsound@... Thanks, Glen Meyer