AL would be the best option, CF is more expensive and in your situation it isn't need, and would be dbl the cost of AL.
With the GV it shortens the shaft so you can stay with the lighter 3" AL and get as much perf and mpg by less weight.
I had my stock one cut down. 100$ out the door. No issues.
Not yet , parts are being shipped now , should be here this week . Will try to post picks of installation .Got any pictures of what you did ?