At 6'1" you might be further ahead with a set of Eagle Mike raising links, especially if you're 200lbs +. Raising links make the rear suspension stiffer with only a very slight raise in height compared to stock.
Also, if you think you want a lower gear, maybe your bike has had the stock 15 tooth front sprocket swapped for a 16? This is a common mod to drop RPM on the highway. For rock crawling you want the 15 or maybe even a 14.
CHECK YOUR OIL OFTEN. Many '08s have a rep for oil consumption at high RPM.