mantamagic

There seems to be a fair amount of money thrown on HKS and Blitz products, with these companites capitalizing on their names.

After scouting round on the internet, it would seem that HKS plugs are indeed Denso plugs rebadged. Blitz plugs are NGK's rebadged.

It seems to be the same exercise with GM plugs, which are Bosch plugs with GM stamped on them.

Iridium plugs are the way forward, as there service life is considerably longer than platinum. Platinum plugs are good for 20,000 (although I don't want to risk them that long!), with NGK iridium good for 30-60,000 and Denso good for 20-30,000 miles

The Denso plug has a 0.4mm electrode and can tolerate a larger plug gap (around 1mm), with the NGK iridium plug having a 0.6mm electrode and therefore needing a smaller gap (around 0.7-0.8).

Iridium is 4 times stronger than Platinum and conducts better, it also has a considerably higher melting point.

Therefore I would state that Iridium plugs are the better performance option than Platinum/Gold & Palladium plugs and that you should not expect to pay any more than £50 a set.

I recently ordered a set for my car from www.spark-plugs.co.uk, for my application (VX Z20LET Engine) it's £30 for NGK Iridium or £44 for Denso iridium power IK20's.

Due to posts on Denso tip's and plug's failing I have gone for good old NGK. Still the best spark plugs manufacturer in the world!