well, one reason besides appearance is that i belive motorbikes should be the only ones with daytime running lights, not cars.
another reason is that this mod gives you the ability to drive without any lights on. it is sometimes helpfull if you go camping and dont want to shine lights at anyone.
but me personally, i hate the way it looks with daytime running lights. looks much better without them. plus it gives you the ability to turn on the lights at one notch (small side lights) without the main lights comming on, looks cool.
I have also been reading on this, since a Bay Area member, soundtrax, wanted me to help him disable his DRL's. This mod will work fine, but if you ever upgrade to HID's it will burn out the bulbs quickly by simply unplugging the harness from the silver ti-tac looking thing above. I will find the thread on NASIOC that explains this, also with pictures.
The proper way to disable the DRL's for good is to take out the glove box. Behind the glove box is the main harness for the DRL's. All you need to do is unplug this harness and you will never have any problems with HID's or anything.
Here is the thread I promised above, about taking out the glove box and disconnecting the MAIN DRL harness, instead of the connector in the engine compartment. This link also has detailed pictures on how to perform the disassembly of the glove box.
And here is a quote from this link from our very own clubWRX.net member cnk:"A lot of people who pulled the one in the engine bay had issues with the DRL's coming back on when they upgraded their lighting to HID's. The module in the engine bay doesn't actually control the DRL's. The actual DRL module is the one behind the glovebox. If you're going to do something, you might as well do it right the first time. It's only 7 screws to take out the glovebox. Takes less that 15 minutes to take it apart, pull the plug, and put it back together. You then don't have to worry about water getting into the open connectors or dirt/grime."