Thank you Philosophico for the response and gruesome photo as proof. I also found a gentleman on eBay who machines the stock SRT6 pulleys down to 69 mm and claims more durability. I suppose that I can always try the aluminum one and always carry the stock pulley and some tools with me. I also found another person who makes shields to prevent the springs from damaging other components as they fly off. It is hard to be a addicted to speed and power. Crackheads got nothing on us.