The aspirin isn't harmful, especially if you're over 30. It's intended to help the obese in mobilization of fats in the blood stream, and unnecessary as part of the stack for those under 20% body fat.
Taurine helps with clen, as the beta agonist robs the body of the vital amino acid, which helps prevent cramping. But as Tron stated, ketotifen isn't needed for ephedrine as it acts on the adrenergic receptors differently.