$70 for a V8
A quick internet search found that they offer longer life for a high cost.
Buying the "long life" feature for a Tiger seems silly. How many miles a year do you drive your Tiger. I seldom put more than a thousand miles a year on either Tiger and when I do it is to do a round trip to a major event.
These long life plugs may make sense for a daily work truck doing 70,000 miles a year.