There is no official certification. Rimfire sparkplugs, although of very high quality, were manufactured for intended use in model engineering and miniature engine building. 

No. The manufacturer of Rimfire has retired and is out of business.

Boots are no longer made, but most users cover the termination with heat shrink.*

Rimfires will spark easily at 5-7,000 volts although I use an electronic CDI ignition that produces about 25,000 volts. Many people use the old timer 3V Modelectric coils that ran on AA batteries and the Rimfires seem to work well, however most of today's high compression engines work much better with voltages of 11,000 or greater and CDI systems offer tremendous reliability and long spark plug life.*

A high voltage test lead wire works well on sparkplugs.  A  22 AWG from Mouser is fine.

A couple suggestions:
ch-ignitions.com
cncengines.com

The Rimfires and Vipers were successfully tested at 20,000 sparks/second.*

The body is steel 12L14 and the electrode is stainless steel.*

Yes, please check the ABOUT page for more.

Items are typically shipped within 1 business day, from St Paul, MN, USA.

Flat rate shipping for all domestic orders is $7.40 and, unless specified or requested otherwise, are delivered via First Class USPS mail.

Flat rate shipping for International orders is $40. Shipping is typically via UPS or DHL, depending on destination and rate.  

Flat rate shipping fees are charged at checkout. If you require additional shipping options, or wish to purchase your own shipping label, please contact us to have the flat rate refunded and to make arrangements to use your label.

International buyers to pay currency exchange costs and any applicable tariffs

Any postage adjustments must be made prior to shipping.