I have searched all over the internet looking for valve stem cores for my '13 Z06. After doing a little research I have found out that the valve stem cores for the metal stems are shorter than the ones for other stems. My current cores are not working properly and are in meed of replacement. I can't find the correct cores for these stems. Any one have line on where to find these cores? I really don't want to go to a tire store and listen to all their bs about how I will need new TPMS sensors etc. Any help would be great.