Warranties are crazy expensive for these unfortunately, but it is definitely at the age where many repairs will need to be done soon to maintain its performance and safety. I suspect a lot of the repairs won't necessarily be covered by the warranty as they are wear related as well. If you have the ability to purchase the $5k warranty outright (ie not finance it into the purchase), then I'd say just put the cash aside and tap it for repairs. Even my 4.4i has been an incredible drain of $$ after about 60k. I'm at 110k now and feel I took care of most of the issues, but it was not cheap!

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2001 X5 4.4i
2002 Honda S2000