There are indeed alternative lamps you might be able to use.. HOWEVER in some states the wording of the vehicle code is such you might get in tribble for using them.. Sadly. I do not have a clue as to which states, and in this case I do understand the reason for the wording so I can not even get political about it. I can only warn of it.
The advice above to get 'em aimed, and perhaps use the specified replacement is the best advice.
Another thing that can dim a lamp is contact resistance. and wire loss. The lamps are designed for 13.6 Volts give or take a tad... But if connections have tarnished, or wires are too small, you might only be getting 10, or less. Finding the voltage loss and fixing it will brighten your day.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times