summerwind , Congratulations ! You have made 20+ postings, which proves, you have a lot of free time on your hands. Thanks for your.... Contributions ??? I hope that buying 2 DLE engines makes you a spark plug expert. Price has nothing to do with quality... Unfortunate that this truth is unlearned. Accept this.. The plug will not cause a crash. You can't even get in the air unless the plug works !! Let it sink in... Pilot error, low altitude, poor build techniques, low flying reign deer, and gale force winds, usually are the crash culprits. Oh yeah... and Test Props too !!! Be ever careful of those dang gammit Test Props !!! Very brave, of you, to have installed one. You'd have been better off with one of those factory DLE spark plugs in your bird. You don't really have any say in regards to what a manufacturer sends with their product,... unless you own the company. Sounds about right. As for plug longevity, a plug that does not last long, is not defective. It is highly unlikely that DLE will advise you that a part to their engine is guaranteed, a near future failure. That is financially unethical. The plug given is enough to test and get started. Distributors can't be held accountable for supplying people with goods they want. Companies with bad products close down. You don't have to appreciate the tester plug that came with the engine. Finance a good plug !!! There is no language barrier here,... just a lack of focus and clarity. In your plight to protect DLE from those who aren't in the know(post #105), How's it going ??? I look forward to hearing your Real World results from your efforts. Thanks for all that was contributed, in your behalf, on DLE spark plugs !!!!