Yup, the problem with removing the amber and then using silver bulbs is that you now have no reflector in the housing so are reliant on the output from the bulb alone to indicate - which at night with HIDs is poor and during the day is even worse.
I found the brightest opposite pin LED indicator bulbs I could find and they are awesome.
As I've only done the front (the rears are silver with a reflector) I don't have a rapid-blink problem (which is sorted by in-line capacitors). No codes thrown on the dash - the car's too old, but does have a field day when you plug in the diag. tool
Thanks for the reply. What do you think of these "built-in resistor" LEDs? Should be bright enough?