Well I've read a lot of good results in terms of dyno numbers and people raving about the BR7EF plugs.

I've done a couple of mods, pulley change, Mechman alternator and a couple of other things including going with the BR7EF NGK plugs gapped at 0.28.

Right away I noticed the car runs terrible so I thought it's the tune, switched to SD instead of MAF and it got a lot better but still not what I wanted.

I then kept chasing my tail, after all these years of tuning for some reason the car would start some days but not others and yet I'd dial in all the IFR's vs. IAT etc.. She would crank but no fire then barely start and be fine with minimal +/- 1 LTFT adjustments.

Needless to say today she wouldn't start at all, the plugs were fouled. Now although I agree they are great for WOT and I noticed I can get away with more timing so more than likely I'm making more power, even with the heatwave we've been having lately getting up to almost 100*F outside they still managed to foul on a daily driver. So if you're the type that start the car drives to the grocery store for 5 mins or whatever you do and park the car, beware these plugs are most likely not for you. Also the idle quality and part throttle were aweful, I could get the tune down to where they would run great! However I then started noticing that the longer the car ran the better they performed, mornings etc... there would be weird surges and wild Trim swings then stabilize.

I also noticed that when you turn the car off and start it back up, right after coming to a stop without letting her idle for a while when she would start, the TRIM's would go crazy negative and for a good 3 minutes they would stay that way. So I'd go into Decel right away turning off fuel and noticed the 02's were still reading fuel for a good 15-20 seconds with injectors off, so there were mis fires hence it would idle a bit rough.

Anywho I threw in a set of old ZR1 plugs I took off a friend's car when doing his plugs and wihtout doing anything the car runs like a dream! Perhaps lesson learned, use these if you go on long trips or mainly beat on the car, and most certainly NEVER tune your car on these plugs such as dialing in your VE etc.. Anything but a perfect tune these plugs will die and fast.

 

I have been suggesting Brisk plugs for years but it still seems I am the only one using them. Do yourself a favor and try a set of Brisk GR14S.... same heat range as NGK 7.
Yes, they are a bit expensive, but I have been using them for 3 years with no issues like you speak of, and I do a lot of short trip, around town driving. I just changed for a new set when changing blowers, and the original ones I had in there for 3 summers were still like new.

 

The best plug choice is a simple copper core NGK TR55 gapped at .040 --Your's are gapped way to close
Plug fouling is normally caused by a RICH condition---
REMEMBER when your car is cold started it is in OPEN LOOP-- until the coolant reaches approx. 140* after warmed and started and above 140* it switches to a timer--that is like 20 seconds----If you are having an open loop rich condition you need to lean down the open loop fueling in the start up fueling areas----If you are having issues after it switches to Closed Loop then than is another issue--
PS do you have an aftermarket CAI ?
What are your LTFT's after it switches to closed loop at idle??

 

I run the ZR1 Iridium plugs. I tried the BR7EFs and the idle and gas mileage went south. Needles to say I won't recommend those for low boost and/or semi-aggressive applications. I know some people use them with great luck but I know it's not for every combo out there.