I've delt with a few cars with 9007 as well as thge (prefered, IMHO) 9005/9006 combo. One of the cars I'm looking at picking up is coming with H13 (or 9008) headlamp bulbs andd was wondering if there is any talk of these around here? A quick search didn't reveal anything terribly useful or interesting... Although it seems the Philips Xtreme Power is available in this spec, and I have been VERY impressed with them in 9007 sizing.
I'm not necessarily looking to upgrade options at the moment, just some info on how these compare to (the appearently previous?) 9007 bulbs and what to expect
There is no such bulb as "9008". The H13 bulb is, conceptually, an optimized HB5 (9007). It is intrinsically a cleaner light source with fewer and better-controlled stray reflections off the bulb walls and filament supports. But like most HB5 headlamps, most H13 headlamps are not very well focused. The Philips Xtreme Power H13 is far and away the best one on the market.
There is no basis to "prefer" a 9006; it is not a very efficient light source. There are much better single-filament halogen headlight bulbs in terms of luminance, flux, focus precision, etc. H1, H7, H11, HIR2...
H13 is indeed basically a refined 9007, though the two are physically and optically non-interchangeable.
There are various errors in the bulb replacement guides published by Sylvania, Wagner, and the others. The data all comes from one guy(!), who gets it by going around to new-car dealers and making a pest of himself at the parts counter. Other nonexistent bulbs listed in the Sylvania guide include "992" (which is actually a 7440A glass wedge T20 amber turn signal bulb…"992" is a production date code!) and "2504" (which is actually a PSX24W…"2504" is a production line code). There are more, but you get the idea.