In the first eight weeks since its website went live, more than 80% of the independent garages involved in the programme promotion have joined online.
NGK uses Boxclever to reward garages which regularly fit its spark plugs, glow plugs and Lambda sensors as replacements during servicing.
Garages can return the boxes and earn points which they can exchange for items such as T-shirts, DVD-players and TVs.
The website now allows registered participants to check their points account online and view other special promotions.
Qualifying for free gifts has been made simpler this year - now garages have to save complete single boxes of NGK spark plugs, glow plugs and Lambda sensors rather than just box tops.
Brian Childs, NGK UK’s deputy managing director, said: "When we launched BoxClever we had no idea just how popular this promotion would become.
"It is already NGK UK’s longest ever running trade promotion."