Yes Gold aka Grandpa spring. Changed mine a couple years ago to this and it makes loading and unloading off the deck much nicer. I also think it will increase the life of the clutch since it doesn't slam together.
I have ran the gold, it engaged at arpund 3200rpm. Was good for edmonton field riding but i wouldnt use it in the mountains. In heavy snow conditions will load up the engine too much and lose snappy throttle acceleration. IMO.
I ride 2010 m8 and use the stock Cat, yellow white and make sure the weights rotate free. Also I put in Thunder Products ABC kit which allows adjustment of the belt to shieve clearence. Just dont set it too tight belt will drag when gets hot mountain riding, .040 to .050" if im correct is about right. The weights are kinda 'tucked in' so if the clearence is way off will cause jerky engagement. Also make sure weights dont have flat spots