[s-cars] Questions about the 9005 bulb "trick"

[Dave Forgie]

Being of Scottish ancestry (i.e. frugal) (forget the sheep jokes - those
are for the New Zealanders), I am interested in the trick where a 65W
9005 bulb is modified to fit in the 9006 (55 W) low beam position of the
OEM DOT headlight housings.  I have down loaded the "More_light.htm" for
the BMW E34 website and have checked out my spare 9005 and 9006 bulbs
and have two questions:

1.  The difference in the position of the filament in the two bulb types
is about 1 mm.  Is this going to cause and problems, i.e. the beam being
out of focus??

2.  The OEM (say Hella) engineers obviously were thinking about
something regarding the ceramic cap on the end of the 9006 low beam
bulb, i.e. heat on the projector lense, focal points, stray light, etc.
What are the downsides of no cap on the end of the 9005 65 W bulb?

Dave F.