Here's a good clarification from Ron at Bus Depot.
Edward

>It depends on which Hellas you have. To explain this I probably have to
>start with what the Bosch is, and is not.  The Bosch is a true H4 headlight.
>Thanks to arcane U.S. D.O.T. FMVSS 108 regulations, you're not supposed to
>use H4 headlights on a car in the United States. (For this reason, I and all
>other vendors sell all H4 headlights as for "offroad use only.")  However,
>according to the same regulations, it's perfectlly fine to use them on
>motorcycles, as long as the manufacturer has obtained the proper D.O.T.
>approval. Bosch makes two versions of their H4's - one which is strictly
>E-code (European and Canadian street legal), and a very similar one that is
>D.O.T. approved for use on motorcycles. The latter one can be identified by
>the D.O.T. marking on the lens, and is the one that is generally preferred
>for Vanagon or Bus use. (See http://www.ratwell.com/technical/BoschH4.html).
>It is our good fortune that Bosch makes this D.O.T. version because that's
>the only reason we are all getting this bargain. One of Bosch's customers
>(Harley Davidson) experienced a sales downturn, resulting in an overstock of
>these headlights, which I in turn bought for way below wholesale.
>
>Hella makes their own conventional H4 headlight, which is relatively
>comparable to the Bosch (although some would argue that the Bosch has a
>slightly preferable beam pattern). If that is what you already have on your
>Vanagon, I can't say I'd bother replacing them. But Hella also makes a
>"Vision Plus" model that is also often erroneously referred to as an H4
>headlight. A better description would be "H4 style," as it actually uses an
>HB2 rather than an H4 bulb. Since it is not actually an H4, it is U.S.
>D.O.T. approved for automotive use, so anyone concerned about enforcement of
>FMVSS 108 can use it worry-free. But the downside is that the HB2's
>performance is widely considered to be inferior to that of a comparable H4,
>and the cost is higher. If this is the Hella that you have, you might notice
>some improvement using the Bosch, although certainly not as substantial as
>if you were upgrading from sealed-beams, as the Vision Plus has already
>gotten you half way there.
>
>In between these options are a wide range of bargain priced H4 headlights,
>mostly made in India or Taiwan. They all come from a few factories that
>private-label them and build to spec (or to price). Most are neither ECE
>(E-code) nor D.O.T. compliant, so they have to meet no recognized standard
>at all.  As a result the quality and performance are all over the place, and
>cannot be predicted by brand name or price. The worst of them can leak when
>it rains, blind oncoming traffic, or in some cases illuminate the shoulder
>better than the road (as some sold in the U.S. were actually designed for
>Indian, UK, or other right-hand-drive markets). The best of them are
>actually pretty decent, and a few even meet ECE specs, although I would not
>put them on the par with a good Bosch, Hella, or Cibie.
>
>As for having to upgrade your wiring, the standard 60/55 watt H4 bulbs draw
>about the same current as the stock sealed-beams and will work with your
>existing wiring (although cleaning up or replacing grounds, or adding a
>relay, can only improve things).  If you move up to an 80/100w bulb you will
>need to add a relay. Most people find that upgrading to the H4's with the
>standard 60/55w bulbs is already a big improvement, and it's a five-minute
>drop-in installation that way, so I tend to advise starting there. If it
>doesn't cut it for you, you can always add a relay and brighter bulbs
>afterwards
>
>Bottom line for all this is, at regular price ($80 to $120 for a pair of
>Bosch, Hella, or Cibie H4's, $35-$50 for a decent generic set), there would
>be a number of options well worth considering. But right now, while you can
>get the Bosch's for the price of the generics (and half the price of any
>comparable top-shelf alternatives), there's nothing else to consider. This
>is a no-brainer.
>
>Link:
>
>  http://busdepot.com/details.jsp?partnumber=0301600118
>
>- Ron Salmon
>   The Bus Depot, Inc.
>   www.busdepot.com
>   (215)  234-VWVW
>
>_____________________________________________
>Toll-Free for Orders by PART # :  1-866-BUS-DEPOT

At 10:20 PM 10/31/2010, Tom Hargrave wrote:
>I dont know why anyone would install motorcycle headlights in a car.
>They arent better, they are different. Motorcycle headlights send out a
>tighter, longer reaching beam while a car headlight sends out a more
>spread out beam. You need the more spreadout car headlight beam to
>safely light the road ahead.
>
>The right solution is to upgrade to newer car HID headlights, assuming
>they are available fo Vanagons.
>
>Tom
>www.towercooler.com
>
>
>Sent from my Verizon Wireless Phone
>
>-----Original Message-----
>From: Tom Boldway <jboldway@HOTMAIL.COM>
>Sent: Sunday, October 31, 2010 6:59 PM
>To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
>Subject: Motorcycle headlight conversion?
>
>Hello, my previous owner spent $451 to get the headlamps converted to
>Bosch motorcycle headlights - "BOSCH H2 000 SAE76 DOT 1305 603 038"
>headlights and the output still kinda sucks. I bought a pair of driving
>lights to go along with this. Anybody ever heard of this conversion
>before?                                    =