I'm looking at switching to an aluminum flywheel as that would save 23 lb over a cast one. Cast flywheels typically weigh 38 lb, steel ones weigh about 30 lb, and Al weighs about 15 lb. I hear it's a little hard to started from a stop with Al, but overall it should really help performance. People spend a lot of money to save a few grams here and there from the rotating assembly, but with the Al flywheel, you can reduce rotating weight A LOT.