Is it a good idea to extend my life span with cybernetics and augmentation with my retirement money?

You have made a lot of assumptions and your plans are based on things that have never existed before. For one example, nobody after the biblical period has lived longer than 120 years. Of more immediate concern is that every country that has tried unbacked paper money has collapsed withing forty years. The USA is now in the 46th year since Nixon abolished gold backing of the USD in 1971, and in the tenth year of a slow, noisy collapse counting from the double top in S&P500 in 2007.

Your 401K almost certainly will be stolen by the government before you can collect it. Greece has already done that, Germany is preparing to do it, and most of Europe and the USA are considering it. The only way to protect yourself is to borrow from your retirement account and buy precious metals which you hide at home where only an honest burglar can steal them.

And forget about the surgeries until you hear that such things are a reality.