I have 17,000 plus miles on my Cobra and Mike has close to 30,000 on two Cobras. I have not had a flat but Mike had one flat on the interstate. One can of flat fix and we back on the road in ten minutes. He did stop at next town and got it repaired. Boy, they cused the flat fix. It's a mess to clean up, but it works. I think it's better than a spare and you can run wider rear tires. I bought four 8" rims but found out very quickly that I needed more rubber on the rear. Sold that set of rims/tires and bought more. I had a mild 5.0 EFI at the time ( 250 - 270 rwhp?). Good tires and great brakes are a must in a Cobra that you drive. You will get rained on if you drive your Cobra weekly.
Dwight
