DID ANY one try these type before?. About 2 month ago I went to a shop to buy some B9EV(2 cycle), but the guy there told me those has been replace with NGK Iridium BR9EIX. so I give these new plugs a try. I think these plugs work very good in my car 13BPP. my NGK R(10.5) never work too well on my 13BPP, it work pretty good on DYNO and willow spring big track. but it was miss fire like **** a BUTTON willow and willow spring street . mabe because I still got a stock ign system or I just not drive hard enought . so do MSD 6A really help.and how many I should put . i plan to put 2 on my car

 

the 10.5 race plugs are a very cold heat range and can foul easily. depending on the outside temp you maybe better off with the 9 heat range. 10.5 seems to work better on the turbo cars. MSD is not needed in my opinion but won't do any damage. as for the availability of the B9EV or BR9EV. I just bought some BR9EV's from my local motorcycle shop(north hollywood honda) so I don't think they are discontinued. maybe they were just out of stock