Whatever you do, make sure you have a plan if you have a blow-out. I switched out to a set of non-run flat performance tires at about 17,000 miles. Thought it was a good idea until.....
My nightmare -- blow out (flat) 2 hours from my home on New Years Eve (Dec 31). Was instantly on the rim and could not drive even 10 feet. A "kit" is not going to help you if you have a major failure. Was a nightmare. BMW Assist was great, but all they can do is tow you to a dealer. That's it.
If this is your "second car" or a "weekend toy", it's a great idea to switch out to a less expensive and better performing non-RF. But....if this is your daily driver, you might want to re-think it.
: 2011 335i Sedan
Gone But Not Forgotten
: 2008 135i Convertible