For completeness (and intellectual honesty), I've added the following information originally posted in another thread:
Aarrrggghhh!!! With all the discussion concerning keeping the low beams illuminated when the high beams are on, I
finally realized that
it can be done without a diode or relay at all ... using just a single wire jumper! You could even insert a simple SPST switch in the jumper if you wanted to be able to switch between standard "two light" high beam mode and "four light" high beam mode.

Please remember that all the discussion concerning the adequacy of the stock Fiero headlight circuitry still applies. I don't think that the stock headlight switch will survive the current demands of four 65 watt H9 bulbs ... at least not for very long. Adding a relay would still be a better solution, IMHO.
[This message has been edited by Marvin McInnis (edited 08-20-2008).]