In my opinion, this is not a wise thing to peruse......for several reasons:
1) A brighter DRL will make it more likely you will forget to turn the main lamps on when needed (unless they are automatic).
2) Almost everything on these cars is controlled by some computer. Screwing with it might break something else.
3) The NTHSA has determined that there is not enough proof that DRLs really work so they are not even required anymore.
IF you REALLY insist that you want brighter lights on in the daytime.......just turn the headlights on manually.
But that's not really good either as your stop lights are harder to notice in the daylight if the tail lights are also ON.