I used a screw on type NGK boot. It isn't formed to fit the hole like the stock boot, but it works.
I changed because I wanted a shorter boot that didn't rub on my turbo charge tube.
you just cut the old one off and screw on the NGK.
NGK spark plug resistor cover #TB05EMA (stock #8636 = black)
You can Google the number and buy them online.
Here is the NGK site if you want more info: NGK Racing Wires