I am building an AF 500 and going to buy a 99' cr 500. I am going to buy the kit that guy sells on banned's website. I was wondering, what is the best cr500 engine out there? opinions??? Power, Weight, etc. aluminum or steel, parts availability, power, durability. I know that pre 88' and post 93' had longer 4/5 gears, better for enduro/trails. give me your opinions?????