I tried the splitfires back when they came out, mainly because I got them for free, I used them for about 3 years, in two different vehicles before I swapped them out. They actually could have been used for maybe another year but decided to go with something different. Didn't notice any noticable gains with anything, they fired fine, didn't notice any misfires either, seemed like a decent plug.
Bosch,?? I stay as far away from those things as possible, especially their enclosed electrode platinums, they sucked, quit working in about 3 months, they were installed in a '88 TPI motor. Swapped out for regular AC Delcos, everything was fine.
When the motor in the Burb was recently rebuilt,'89 TBI, I had some issues with the new AC Delcos, was getting misfires, especially when cold, I decided to swap them out with some of the AC Delco "Platinum Professional" or something like that,,before the long drive to Indiana from Phoenix,AZ, and they worked great, no misfires or anything, they do have the fully exposed ground electrode tip just like the standard plugs.
Never got into the hype so much with the multiple tipped plugs, spark is going to travel the path of least resistance anyways, so why do you need 2-3-4-12 electrodes. I know I used the splitfires, but again, they were free
