Limitations on warranties are disfavored in the law. That means that judges will look for ways not to enforce the limitation. It is usually possible to enforce limitations if they are plainly and clearly spelled out, were part of the bargain, and do not offend social norms. But each case is different. Limitations in commercial contracts are more likely to be enforced than limitations in contracts with consumers. There are also some laws that limit your ability to limit warranties. This is not an area where you should not be drafting clauses yourself.
Anything you add will have more weight than printed language. It is often useful to add what you are told about the product. Rather than trying to exclude things from the waiver language, if you can just strike the waiver language and intitial it