[Dave at Pelican Parts]

Quality control on the cheapie Bosch platinum plugs (the ones with just a tiny speck of platinum in the center electrode) has been pretty poor. I know several people who have had the platinum un-bond itself from the rest of the plug and come bouncing out into the combustion chamber, or weld itself to the outer electrode.

As far as I can tell, the "+4" plug (and its cousin that only has two electrodes) are just the same crappy plug with extra outer electrodes. I would recommend staying away from any of them, frankly. I also have heard anecdotal evidence (e.g., stories) about other plugs curing minor driveability problems when they were installed in place of Bosch platinums. In fact, I had a no-start in a previous 914 that seemed to be in part due to those plugs.

Note that Bosch makes some very good plugs, including some platinum ones. But the good platinums are pretty pricey and harder to find than the cheapie ones.

I cannot recommend a replacement plug for the BMWs, though, as I haven't been cralwing around in them enough. In my 914, I use Bosch Copper plugs. In my Japanese car, I use NGKs. Both are fine plugs, but may not be up to snuff in the BMW application. (Might be great, might require replacement sooner than the regular service interval, or something else may happen--I don't have any data about that yet.)

But I would at least consider some alternative to the cheapie Bosch platinums. I consider them to be junk.

--DD